The Journal of the Quekett Microscopical Club

AL 8

The late Professor E. A. Minchin, M.A., F.R.S.

Frontispiece]

[See page 669

THE JOURNAL

OF THE

(fyukttk

Microscopical Club

EDITED BY
A. W. SHEPPARD, F.Z.S., F.R.M.S.

SECOND SERIES.

VOLUME XII.

1913-1915.

.--.._

...

[Published for the Club]

WILLIAMS AND NORGATE,

14. Henrietta Street, Covent Garden. London,
and 7, Broad Street, Oxford.

PRINTED BY
HAZELL, WATSON AND VIXEY, LD.,
LONDON' AND AYLESBURY.

Ill

C O N T E N T S .

PART No. 72. APRIL 1913.

Papers.

E. Heron-Allen. F.L.S., F.R.M.S., awl A. Euiland, F.R.M.S.
The Foraminifera in their Role as World- builders : A
Review of the Foraminiferous Liiw stones and Other Rocks
of th^ Eastern and Western Hemispheres (Plates 1-3)

W. M. Bale, F.R.M.S. Notes on Some of the Discoid Diatoms .

Henry Whitehead, B.Sc. Some Notes on British Freshwater
Rhabdocoelida a Group of Turbellaria (Plate 4)

Charles F. Rousselet, F.R.M.S. The Rotifera of Devils Lake,
with Description of a New Brachionus (Plates 5 and (3)

Arthur Dendy, D.Sc, F.R.S. President's Address By- Pro-
ducts of Organic Evolution (Plate 7) .

David Bryce. On Five New Species of Bdelloid Rotifera (Plates
8 and 9) ........

Notes.

E. M. Nelson, F.R.M.S. A New Low-power Condenser

E. M. Nelson. F.R.M.S. Xavicula rhomboides and Allied Forms

E. M. Nelson, F.R.M.S. On Microscope Construction and the

Side Screw Fine Adjustment (Figs. 1 and 2 in text)
E. M. Nelson, F.R.M.S. Note on Pleurosiqma angukitum (Figs.

3 and 4 in text) ........

E. M. Nelson, F.R.M.S. Actinoci/clus Ralfsii and a Coloured

Coma .... .....

Notices or Books ........

PAGH

1

17
4.3
57
05

83

95
90

90

98

100
101

Proceedings, etc.

Proceedings from October 22nd, 1912, to February 25th, 1913,
inclusive .........

Forty-seventh Annual Report, 1912 r

Report of the Treasurer. 1912 .

103
113

120

PART No. 73, NOVEMBER 1913.

Papers.

E. Heron-Allen, F.L.S., F.G.S., F.R.M.S., and A. Earland,
F.R.M.S. On some Foraminifera from the North Sea,
dredged by the Fisheries Cruiser " Huxley " (International
North Sea Investigations England) (Plates 10 and 11) .

12 1

'\J

-

IV CONTENTS.

PACK

C. D. Soar, F.L.S., F.R.M.S. Description of Arrhenurus Scour-
fieldi and Acercus longitarsus, Two New Species of Water-
mites (Plates 12 and 13) 130

G. T. Harris. The Collection and Preservation of the Hydroida 143

T. A. O'Donohoe. The Minute Structure of Coscinodiscus
asteromphalus and of the Two Species of Pleurosigma,
P. angulatum and P. balticum . . . . .155

Henry Sidebottom. Lagenae of the South-West Pacific Ocean

(Supplementary Paper). (Plates 15-18) . . .101

James Murray, F.R.S.E. Gastrotricha (Plate 19) . . 211

Notes.

Edward M. Nelson, F.R.M.S. On a New Method of Measuring

the Magnifying Power of a Microscope . . ,239

Proceedings, etc.

Proceedings from March 25th, 1913, to June 24th, 1913 . 245

Obituary Notice : Rt. Hon. Sir Ford North, F.R.S., F.R.M.S. . 258

PART No. 74. APRIL 1914.
Papers.

Arthur Dendy, D.Sc, F.R.S. President's Address Organisms

and Origins ........ 259

S. C. Akehurst, F.R.M.S. A Changer for Use with Sub-stage

Condensers (Figs. 1 and 2) . . . . . .277

S. C. Akehurst, F.R.M.S. A Trap for Free-swimming Or-
ganisms (Fig. 3) . . . . . . . . 279

E. M. Nelson, F.R.M.S. An Improved Form of Cheshire's

Apertometer (Fig. 4) . . . . . . .281

F. J. Cheshire, F.R.M.S. Two Simple Apertometers for Dry

Lenses (Figs. 5 and 6) ..... . 283

M. A. Ainslie, R.N.. B.A., F.R.A.S. A Variation of Cheshire's

Apertometer (Figs. 7 and 8) . . . . . 287

James Burton. On the Disc-like Termination of the Flagellum

of some Euglenae . . . . . . 29 J

E. M. Nelson, F.R.M.S. On the Measurement of the Initial

Magnifying Powers of Objectives (Fig. 9) . . . 295

S. C. Akehurst, F.R.M.S. Some Observations concerning Sub-
stage Illumination (Plates 20-22) . . . .301
T. A. O'Donohoe. An Attempt to Resolve and Photograph

Pinnularia nobilis ....... 309

N. E. Brown, A.L.S. Some Notes on the Structure of Diatoms

(Plate 23) 317.

Notes.

James Burton. On a Method of Marking a Given Object for

Future Reference on a Mounted Slide. . . .311

CONTENTS. V

Vk v.
}). M. DRAPER. A Live Box for the Observation of Insects and

Similar Objects ........ 313

15. M. Draper. Dark-ground Illumination with the Greenough

Binocular ...... 313

E. M. Nelson. F.R.M.S. Amphvpleura Lindheimeri . . 315

Notices of Books ........ 339

Proceedings, etc.

Proceedings from October 2Sth, 1013, to February 24th. 1914.

inclusive ......... 340

Forty-eighth Annual Report, 1913 314

Report of the Treasurer, 1913 302

List of Members . ...... i xxxii

PART No. 75. NOVEMBER 1914.

Papers.

Edward M. Nelson. F.R.M.S. A New Object Glass by Zeiss.

and a New Method of Illumination (Figs. 1-3) . . . 3

Edward M. Nelson. F.R.M.S. A New Low-power Condenser

(Fig. 4) 367

Edward M. Nelsox. F.R.M.S. Binocular Microscopes (Fig. 5) . 309

A. E. Hilton. Notes on the Cultivation of Plasmodia of Badhamia

utricularis (Fig. 0) ...... 381

A. A. C. Eliot Merlin, F.R.M.S. On the Minimum Visible . 385

C. F. Rousselet, F.R.M.S. Remarks on Two Species of African

Volvox 393

C. F. Rousselet, F.R.M.S. Report on the Conference of Dele-
gates of Corresponding Societies (British Association) held
at Havre ......... 395

( '. F. Rousselet, F.R.M.S. Pedalion ou Pedalia ; une question

de nomenclature dans la classe des Rotiferes . . .397

Proceedings, etc.

Additions to the Library since January 1914 . . . 399

Additions to the Club Cabinet since October 1912 ... . 401

Proceedings from March 24th to June 23rd. 1914, inclusive . 411

Obituary Notice : Dr. M. C. Cooke 422

Table for the Conversion of English and Metrical Measures . . 424

PART No. 76, APRIL 1915.

Papers.

R. T. Lewis. F.R.M.S. The Early History of the Quekett

Microscopical Club . . . . . . 42 ~>

D. J. Scourfield. F.Z.S., F.R.M.S. A New Copepod found in

Water from Hollows on Tree Trunks. (Plates 24 and 25) 431

VI CONTENTS.

PAGE

E. A. Minchin, M.A., F.R.S. Some Details in the Anatomy of the

Rat Flea (Ceratophyllus fasciatus). (Plates 26-32) . .441

Arthur Dendy, D.Sc., F.R.S. President's Address. The Bio-
logical Conception of Individuality .... 465

W. Williamson, F.R.S.E., and Charles D. Soar. F.L.S.,
F.R.M.S. British Hydracarina : The Genus Lebertia.
(Plates 33 and 34) 479

J. W. Gordon. A " New " Object Glass by Zeiss (Figs. 1 and 2) 515

G. T. Harris. Microscopical Methods in Bryological Work . 52 !

Proceedings, etc.

Proceedings from October 27th, 1914, to February 23rd, 1915,

inclusive . . . . . . . . .537

Forty- ninth Annual Report, 1914 . . . . . .551

Report of the Treasurer, 1914 . . . . . . 558

Obituary Notice : F. W. Millett, F.G.S., F.R.M.S. . . . 559

PART No. 77, NOVEMBER 1915.

Papers.

M. A. Ainslie, R.N., B.A., F.R.A.S. An Addition to the Ob-
jective (Figs. 1 and 2) ..... 561
A. A. C. Eliot Merlin, F.R.M.S. Notes on Diatom Structure . 577
G. T. Harris. A Note on the Slides of Fissidentaceae in the

Q.M.C. Cabinet 581

A. E. Hilton. Further Notes on the Cultivation of Plasmodia

of Badhamia utricularis ...... 585

James Burton. Hydrodictyon reticulation .... 587

E. M. Nelson, F.R.M.S. Various Insect Structures . . . 593

J. W. Evans, D.Sc, LL.B. (London). The Determination of
Minerals under the Microscope by means of their Optical

Characters (Plates 35-37) 597

David Bryce. On Five New Species of the Genus Habrotrocha

(Plates 38 and 39) 631

Notices of Books (Plate 40) ...... 643

Proceedings, etc.

The Club Cabinet, Additions to . . . . .646

Proceedings from March 23rd to June 22nd, inclusive . . 653

Obituary Notice : E. A. Minchin, M.A., F.R.S. (Portrait) . 669

Index to Volume XII. . . . . . . . 673

Vll

LIST OF ILLUSTRATIONS.

PLATES.

Portrait of the late Prof. E. A. Minchin. M.A., F.R.S., Facing page 501

1-3. Foraminiferal Limestones.

4. Rhabdocoelida.

5. Asplanchna Silvestrii Daday.

6. Rotifera.

7. Spicules of Tetraxonid Sponges.

8, 9. New Species of Bdelloid Rotifera.

10. Foraminifera from the North Sea.

11. Cornuspira diffusa Heron- Allen and Earland. Sand Grains,

etc., from the Bottom Deposits.

12. <$ Arrhenurus Scour fieldi sp. nov.

13. q Acercus longitarsus sp. nov.

14. Structure of Pleurosigma bait ten m.

15-18. Lagenae of the South-West Pacific Ocean.

19. Gastrotricha.

20. View of Back Lens of Objective with P. angulatum in focus.
21, 22. Resolution with Annular Illumination.

23. Structure of Diatoms.
24, 25. Moraria arboricola sp. nov.
26-32. Anatomy of the Rat Flea.
33, 34. The Genus Lebertia.
35-37. Examination of Minerals.
38, 39. Xew Species of Habrotrocha.

40. Rhizopoda.

FIGURES IN THE TEXT.

Page 98. Side-screw fine adjustment.
,, 99. Upper and lower membranes in P. strigusum and P. balti-

cum.
277. A changer for sub-stage condensers.

,, 280. A trap for free- swimming organisms.

,, 281. An improved form of Cheshire's Apertometer.

,, 285. Two simple apertometers for dry lenses.

VJ11 LIST OF ILLUSTRATIONS.

Page 288. A variation of Cheshire's Apertometer.
- j 8J. ,, ,, ,,

298. The measurement of the initial magnifying power : diagram

to show relative position of apparatus.
32Q. Structure of pores in P. balticum according to O. Miiller.
365. Diagram showing method of illumination.

oOO. ,, ,, ,, ,,

3C8. Centring stop-holder.

374. Diagram of eye and Ram~den disc.

383. Exhibition of plasmodia.

517. Diagram illustrating a " new " object-glass.

" 10 ' J ? ? >

567. An addition to the objective : diagram.
504. Various insect structures.

-3

THE JOURNAL : V

OF THE

<iuhcii $$t c rose opt cal dDInIr

THE FORAMINIFERA IN THEIR ROLE AS WORLD-
BUILDERS: A REVIEW OF THE FORAMINIFEROUS
LIMESTONES AND OTHER ROCKS OF THE
EASTERN AND WESTERN HEMISPHERES.

By Edward Heron-Allen, F.L.S., F.R.M.S., axd
Arthur Earland, F.R.M.S.

{Read October 22nd, 1912.)

Plates 1-3.

" Life , as we call it, is nothing but the edge of the boundless Ocean of
Existence where it comes on Soundings." 0. W. Holmes, The Pro-
fessor, V.

Our late President, Prof. E. A. Minchin, F.R.S., in his last
Presidential Address * dealt with certain organisms which he
regarded as the simplest existing living structures, and speculated
on the Origin of Life in this planet. Subsequently at the British
Association Meeting at Dundee he led a most interesting dis-
cussion on the same subject, a discussion which left those who
had the privilege of listening to it convinced of one fact at least,
viz. that no two of the eminent men who took part in the debate
were agreed on any single point. But as the earliest forms
of life were necessarily of such a simple nature that they could
oy no possibility have been preserved as fossils, the interest
of geologists may almost be said to commence with the stage
in which life had become endowed with a sufficiently complex
structure to leave recognisable remains in the geological record.

The Foraminifera would seem to constitute such a group. Of
extremely simple structure, mere protoplasm without differenti-
ation other than the nucleus, they yet possess the power either
of secreting a solid shell from the mineral salts absorbed from

* Journ. Q.M.C., Ser. 2, Vol. XI. p. 339.
Jourx. Q. M. C, Series II. No. 72. 1

*)

E. IIIRON-ALLEN AND A. EARLAND ON THE FORAMINIFERA

their surrounding medium, or'of building up adventitious shells
by the co-ordination of foreign material obtained from their
immediate environment. These shells, from their minute size
and composition, are peculiarly adapted for preservation as
fossils.

Hence, whatever the origin of life may have been, we might
reasonably expect that among its earliest records would occur
Foraminifera of simple and ancestral types, and that subsequent
geological periods would show a constant progression in their
development. Such, however, is not the case. So far as our
geological knowledge carries us at present, the Foraminifera
make their first appearance in the rocks in a highly differentiated
stage, and among the earliest recognisable groups are many species-
which are still existing and dominant types to-day.

It is not so very many years, less than half a century in fact,
since the sensational discovery of Eozoon Canadense (1) (2) (3) in
the Laurentian rocks of Canada was hailed as evidence that the
oldest fossil was, as might have been expected, a rhizopod. Into
the long warfare which was waged round this fossil, in which the
late Prof. K. Mobius took an active part (22), it is not proposed
to enter in detail. But there was at the time of its discovery
no greater authority on the Rhizopoda than the late Dr. W. B.
Carpenter, a former President of this Club. He threw the whole
weight of his authority into the scale in favour of the foramini-
feral nature of Eozoon, and to the last was convinced of the
soundness of his belief. But the balance of evidence has turned
against him, and since his death but little interest has been
shown in the question, Eozoon having been relegated by more or
less general consent to the mineral kingdom.

We are, however, again threatened with a renewal of the
controversy, for Mr. It. Kirkpatrick, of the British Museum,
has recently announced in Nature that he is in possession of
fresh evidence of the foraminiferal nature of Eozoon, and will
shortly publish it. The microscopical world will no doubt await
this evidence with interest, not unmixed, perhaps, with some
trepidation at the reopening of this chose jugee. From the point
of view of the subject of our paper, viz. " The Foraminifera as
World-builders," definite proof of the rhizopodal nature of
Eozoon would be very welcome. Eozoon, whatever its nature
may be, occurs in enormous reefs in the Laurentian rocks of

IN THEIR ROLE AS WORLD-BUILDERS. 3

Canada and elsewhere, and we should thus have evidence that
even at this early stage of the world's history, the Foraminifera
had commenced to play that important part in the formation
of strata which they have continued in nearly all the successive
periods of geological history, and which is still proceeding in
the deep sea to-day. It is no exaggeration to say that, in
spite of their diminutive size, the Foraminifera have played,
and are still playing, a greater part in building up the crust
of the earth than all other organisms combined.

Dismissing Eozoon for the present as incertae sedis, we find
that the only other pre-Cambrian records which can be associated
with Foraminifera are the peculiar bodies described by Cayeux (4)
from certain quartzites and pthanites of the pre-Cambrian strata
of Brittany. These are, however, of such minute size compared
with other Foraminifera that their nature cannot be accepted
on the evidence hitherto available.

It appears, therefore, that at present we have no unquestionable
records of Foraminifera in pre-Cambrian rocks ; but it is quite
possible that such discoveries may be made in the future, as fossils
of a higher type have been found, and it seems unlikely that
Foraminifera did not, or could not, exist in seas capable of
supporting such higher forms of life.

When, however, we come to the Cambrian strata we find the
Foraminifera flourishing, and already marked by numerous widely
separated types. So long ago as 1858 Ehrenberg (5) figured
some internal glauconitic casts of Foraminifera from a clay near
St. Petersburg, which is known to be of Lower Cambrian age.
According to Chapman (9) these casts are referable to at least
five genera, viz. Verneuilina and Bolivina (family Textularidae),
Nodosaria (family Lagenidae), Pidvinulina and Rotalia (family
Rotalidae).

Now it is noteworthy that none of these genera are of simple
or primitive types, but are all comparatively complex in the
arrangement of their chambers, and representing three distinct
types of construction. Hence in this earliest geological record
we find the group already well established, and markedly
differentiated in structure. No monothalamous or primitive
type appears in this earliest list, although we may be sure
that they must have been in existence, both then and during
antecedent ages.

4 E HERON-ALLEN AND A. EARLAND ON THE FORAMTNIFERA

Since the time of Ehrenberg there have been other discoveries
of Cambrian Foraminifera in America (6) (7) and Siberia (8).
We have not had an opportunity of seeing either of these reports,
but it may be noted that the New Brunswick rocks furnished
representatives of the pelagic genera Orbulina and Globigerina
(family Globigerinidae), while the Siberian rock is described as
assuming an oolitic structure on account of the numerous Fora-
minifera which it contains. It is therefore apparent that the
Foraminifera had already assumed that dominant position which
they have ever since maintained in the biology of the sea.

Turning to our own country, the oldest Foraminifera yet
recorded are those described by Chapman (9) from a limestone
of Upper Cambrian age near Malvern (PI. 1, fig. 1). This record is
'of great interest because all the Foraminifera described are either
monothalamous (genera Lagena, SpiriUina) or polythalamous
shells of simple type (genera Nodosaria, Marginulina, Cristel-
laria). As will be seen from the rock section figured by Chapman,
the Foraminifera of one genus, SpiriUina, form a considerable
proportion of the entire mass of the rock (PI. 1, fig. 1). The other
species described are stated to have been of very rare occurrence.
Now SpiriUina is one of the simplest conceivable types of rhizo-
podal shell structure, an undivided tube coiled on itself in one plane,
iand is theoretically one of the forms which might be expected
to turn up in the earliest records. Chapman has on certain
minor points of structure instituted a new species {SpiriUina
Groomii Chapman) for this Cambrian type, but it appears to
be nothing more than a variety of SpiriUina vivipara Ehrenberg,
a species which at the present day occurs on muddy bottoms
of moderate depth in all parts of the world.* So far as we
are aware, however, there is no other record of its occurrence
in sufficient abundance to form a noticeable constituent of any
deposit, recent or fossil. In recent dredgings it cannot be
described as an abundant species.

In the next period, the Silurian, there are many records (10)
(11) (12) (13) of Foraminifera, but they do not appear to be
numerous. Brady (12) records and figures four species of the

* Since this was written specimens resembling SpiriUina Groomii (Chap-
man) have been found in dredgings made in Blacksod Bay, Co. Mayo, and
also in the Moray Firth. They will be described and figured in the
forthcoming report on the Foraminifera of the Clare Island Survey.

IN THEIR ROLE AS WORLD-BUILDERS. 5>

simple type Lagena, which are still existing, and of world-wide
distribution. These and the Spirillina Groomii of Chapman
(= S. vivipara Ehrenberg) are therefore probably the oldest
living types now in existence.

Of greater interest is the recording by Chapman (14) and
Vine (15) of two genera of arenaceous Foraminifera, viz. Hyperam-
mina and Stacheia from rocks of the Wenlock series. These
constitute, so far as we are aware, the earliest evidence of the
existence of arenaceous Foraminifera. The geological record
does not furnish any evidence in support of the theory, so fre-
quently postulated, that the earliest Foraminifera were types
Avith adventitiously constructed tests \ nor do we see any reason
for accepting this theory. The property of secreting mineral
salts from the surrounding medium is common to organisms of
all grades, whereas the power of selecting and utilising foreign
material seems to indicate a later and higher stage of develop-
ment. There appears to be no geological reason why the
composite tests of arenaceous Foraminifera should have escaped
fossilisation, when the delicate shells of -calcareous genera were
preserved, had the two groups been in existence together in pre-
Silurian times.

The Devonian period, according to Chapman (16), presents
but a single record of Foraminifera, viz. those discovered by
Terquem (13) at Paffrath in the Eiffel. Chapman comments
on the singular absence of Foraminifera in the Devonian seas,
where the conditions for their existence appear to have been
favourable.

With the next period, however, the Carboniferous, the Fora-
minifera first begin to justify the title of our paper as Worldr
builders. Various genera make their appearance in such
numbers as to form enormous deposits. In the lower Carbonif-
erous strata the large arenaceous species known as Saccammina
fusuliniformis (McCoy) = S. Carteri (Brady) (17) is the principal
constituent of enormous areas of limestone in Great Britain and on
the Continent (PI. 1, fig. 2). The upper Carboniferous limestone,
on the other hand, is in most regions of the world largely built up
of the shells of Fusulina, a perforate foraminifer belonging to
the family Nummulinidae. Other genera which are largely
concerned; in the formation of Carboniferous limestones are
'Endothyra\i^\. 1, fig. '6) and Archaediscus, while in this period

6 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA

occur the first records of two genera, Amphistegi?ia and Nura-
mulites, which in later times were destined to play an important
part in the formation of the world's crust.

The Permian and Permo-Carboniferous rocks show a decline
in the importance of the Foraminifera. Perhaps it would be
more correct to say that there is a falling off in the records of
those large and dominant types which marked the Carboniferous
period. Foraminifera of many different genera occur in the
Permo-Carboniferous rocks, but they are usually of compara-
tively small size, and so do not readily form a basis for rock
formation. But in New South Wales and Tasmania, Nubecularia,
which is the lowest type of imperforate foraminifer, forms a
principal constituent of some limestones (18) (PL 1, fig. 4).

TheTrias yields no strata in which Foraminifera are the principal
constituent. Foraminifera occur in many horizons, but do not
constitute any large proportion of the fauna. Perhaps the
richest deposit is that described by Chapman (19) from Wedmore
in Somerset.

Similarly in the Jurassic period, the Foraminifera, although
often varied and abundant, are not responsible for any important
proportion of the whole bulk of the formation. They are often
confined to limited zones, in which they occur in great abundance,
but the species are nearly all minute and completely masked as
to external appearance by other material. The most important
feature of this period, however, is the sudden bursting into active
existence of numerous hyaline types, principally Lagenidae,
hitherto more or less unknown. They occur in the clays of the
Lias of the Continent in enormous variety, passing insensibly
from one species into another, and the meticulous precision of
Terquem and others who have monographed these strata has
embarrassed the rhizopodist with a wealth of synonyms.

Up to this period the arenaceous Foraminifera have not presented
any great diversity of forms, although, as we have seen, certain
genera (Saccammina, Endothyra, etc.), have played an important
part in building up strata. But Haeusler (20) (21) has de-
scribed a most interesting series of arenaceous types from a
sandy marl of Jurassic (Oxfordian) age in the Canton of Aargau
(Switzerland), which includes many genera now known to us
only from deep water. It is altogether one of the most pro-
nounced and characteristic rhizopodal faunas recorded in the

IN THEIR ROLE AS WORLD-BUILDERS. 7

fossil condition. The occurrence of this rich series of genera,
some of which appear to be confined to this formation while
others are hardly known except in the recent condition, suggests
that the arenaceous foraminifera have, with few exceptions, always
been confined to the deep sea, and that their scanty geological
history may be due to that fact, and to the rarity of ancient deep-
sea deposits.

Passing to the Cretaceous period, we find the Neocomian and
Aptian strata comparatively devoid of recognisable foraminiferal
remains. But it is almost certain that Foraminifera of the
smaller types existed in enormous numbers in the seas of these
periods, leaving their evidence behind them in the shape of the
glauconitic casts and grains which bulk so largely in the Green-
sands.

The Gault of England and the Continent contains a rich and
varied foraminiferal fauna running into several hundred species.
But although the Rhizopoda must have swarmed in the Gault
seas, they do not constitute any large percentage of the total
mass of the formation, and are often confined to limited zones.

The same remark may be applied to the numerous beds of
chalk ranging from the Chalk Marl to the Upper Chalk. It is
one of those popular beliefs which die so hard that chalk is made
up entirely of the shells of the Foraminifera, and the textbooks
and microscopical works abound with statements to that effect.
Some of the methods suggested to students for the obtaining of
specimens can only have originated in the fertile brains of the
authors. The beginner is instructed to obtain a lump of chalk
and scrub it to fragments with a toothbrush under water ; or to
place some lumps in a bag and smash them up with a hammer,
subsequently kneading the mass under a tap until the water runs
away clear. It is needless to say that such methods can never
produce anything but debris and disappointment. These methods,
together with directions for the adequate preparation of chalk
material for examination, have been fully discussed by Heron-
Allen in his " Prolegomena " (23).

There are very few zones in the Chalk which do not contain
Foraminifera, but their number is as a rule small compared with
the whole bulk of amorphous matter. But it is probable that
in the Chalk sea the Foraminifera really abounded, and
that the amorphous carbonate of lime is derived largely from

8 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA

their comminuted and dissolved remains subsequently reprecipi-
tated.

Certain zones of the Chalk, notably the zones of Holaster planus
and Micrdster, yield Foraruinifera in larger numbers, but even
here a section of the rock will show their limited distribution^
The bulk of the organic remains will be found to consist of small
spherical bodies which when cut in section show as rings (PI. 2 r
fig. 1). These, the so-called " Spheres " of the chalk, are perhaps-
the origin of the belief that chalk is built up of the shells of
Foraminifera. But whatever the " Spheres " may be, we are
convinced that they are not Foraminifera. Their nature is still
in doubt, although they have been relegated in turn to the
Foraminifera, the Radiolaria and the Diatomaceae. Mr. W..
Hill, F.G.S., of Hitchin, whose knowledge of the microscopic
structure of chalk is unrivalled, and who has devoted many years-
to the study of these " Spheres," has published a scheme for the
division of the Chalk into zones, based on their occurrence and
numbers (32), but he is still unable to explain their origin and
nature. We suggest that they may be the chitinous tests
Of flagellate infusoria such as are found in great numbers in the
sea to-day, of practically identical size and shape.

The Chalk of Maestricht is rich in Foraminifera, and may
be regarded as the starting-point of the rich Foraminiferal
fauna of the Tertiary period, as it contains many large genera r
OrbiioliUs, Operculina, Orbitoides, etc.> which reached a maxi-
mum of development and distribution in Eocene and Miocene
times.

Passing into Tertiary times we reach the Golden Age of the
Foraminifera; the age in which they were to reach their
maximum development both as regards size and abundance, and
to leave their remains in great beds extending across whole
continents, and often of an enormous thickness.

These Tertiary Foraminifera are very sparingly represented
in Great Britain. The London clay, although it contains a rich
rhizopodal fauna in a limited zone, is on the whole absolutely
barren, and the Thanet Sands and Woolwich and Beading beds
have yielded few records.

In the Bracklesham beds of Hampshire, however, we find a
zone almost entirely composed of two or three species of Nummu-
lites. At Selsey Bill the foreshore at low tide, on the east shore,

IN THEIR ROLE AS WORLD-BUILDERS.

is for a large area covered with an exposure of this zone (the-
41 Park " beds), and one cannot walk without crushing vast
agglomerated masses of Nummulites laevigatas, extending for
miles and occupying broad areas between tide-marks.

Off the extremity of Selsey Bill lies the extensive reef known
as "The Mixon." It is exposed at low tide, and is then found
to be a limestone principally composed of one species of fora-
minifer, Alveolina Boscii Def ranee. Other species (notably a large
alveoliniform Jliliolina, Nummulites, and a large Polymorphina)
are to be found in the rock, but this is dominant (PL 2, fig. 2).
Alveolina Boscii, which has built up enormous areas of limestone
extending across Southern Europe to the Himalayas, is still in
existence to-day, and is now forming similar deposits off many-
tropical shores. The Selsey specimens the only ones to be found
in Great Britain are indistinguishable from those to be dredged
in shallow water to-day, off the Great Barrier Reef of Queensland
and in many other places (24).

At Stubbington and its neighbourhood, in Hampshire, smaller
types of Nummulites, viz. Nummulites elegans and JV. variolaria r
are to be found in similar abundance.

Turning to the Continent, we find these Nummulitic and
Alveoline limestones developed to an incredible extent. With
interruptions here and there, they spread in a broad band across-
Europe, Asia and Northern Africa to the Himalayas, attaining
in many places a thickness of several thousand feet (PI. 2, fig. 3).
The species vary with the zone and locality, but, as a rule, the-
whole rock is built up of their more or less perfect remains, and
undeft the microscope the very debris in the interstices of perfect
specimens is found to consist of their comminuted remains-
(Pl. 2, fig. 4 and PI. 3, fig. 1).

Among the more familiar instances of Nummulitic limestone-
may be mentioned the Pyramids of Egypt, which are built of
limestone quarried in the neighbouring Mokattam Hills, largely
composed of a single species of Nummulite N. Gizehensis (Ehren-
berg). We illustrate in Plate 3, fig. 1 a section through a micro-
spheric specimen of this Nummulite, one of a series collected for us
by Mrs. A. M. King, F.R.M.S. The peculiarity of these remains
struck the geographer Strabo, who accounts for their presence in
the limestone by asserting that they were the petrified remains
of lentils from the rations of the ancients who built the

10 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA

Pyramids.* They are to this day known locally as " Pharaoh's
beans." t

Philip de la Harpe begins his Monograph on the genus (27)
with the words, " Egypt is the classic land of the Nummulites,"
and Dr. Carpenter in his Introduction (28) passes in review the
legends which have attached themselves to this organism, from
Herodotus (?), Pliny (?) and Strabo to the learned Clusius, who
refers to " the popular belief of the Transylvanians that they
were pieces of money turned into stone by King Ladislaus, in
order to prevent his soldiers from stopping to collect them just
when they were putting the Tartars to flight ! " J

Tt may be remarked that Prof. Haug has suggested (31)
abolishing the Lyellian nomenclature of geological periods for all
epochs later than the Cretaceous, and the redistribution of the
strata into Nummulitic, Neogene, and Quaternary. He suggests
that the Nummulitic, whose classification is founded solely upon
this foraminifer alone, shall be divided into the Eo-Nummulitic,
which will comprise the Montian, the Thanetian, and the Lon-
donian (names which speak for themselves), the Meso-Nummu-
litic, which will comprise the Lutetian and Ludian, and the
Neo-Nummulitic, which includes all strata from the Lower
Oligocene up to the dawn of the Glacial Period which com-
mences his Quaternary.

As a rule these two dominant types, Alveolina and Nummulites,

* Strabo, Geographica, lib. xvii. cap. i. 34: cpaal d'airoXidudrji'a.i \el\pava
tt?s rdv epya^ofxtvocv rpocprjs. ovk direoiKe. See the note on this passage in
Canon Rawlinson's translation (1860).

f In spite of the fact that Herodotus (who has been credited with
Strabo's observation on the Nummulites) expressly states (Euterpe, IT. 37)
that the Egyptians never grew or ate beans in any form.

X Clusius (i.e. Charles de l'Ecluse, 1526-1609), in Caroli Clusii et aliorum
vpistolae, Paris (Epistola xxxvii.), thus records the matter : " Intellexi item
genus quoddam lapillorum planorum et quasi circino in orbem ductorum
inveniri in montibus qui Pannoniam a Daciasive Transilvania disterminant,
quorum alii auri, alii argenti colorem referunt et characteribus insigniti
videntur sed incognitis. Ferunt Ladislaum regem quum Tartaros praeda et
spoliis onustos persequeretur atque metueret, ne militum suorum avaritia
et ignavia, qui thesauris per viam stratis ab hostibus inhaerebant, victoria
illi e manibus eriperetur, a Deo petiisse ut nummi illi et pecunia ab hosti-
bus in via relicta in lapides mutarentur, quo militem sic delusum alacriorem
haberet in persequendo hoste." A passage contemporary with, if it should
not precede, Mr. C. D. Sherborn's earliest reference to Conrad Gesner
(1566).

IN THEIR ROLE AS WORLD-BUILDERS. 11

do not exist together, but the transition from one dominant to
the other is often quite sharp. We show a section from Sherani,
on the N.W. frontier of India, illustrating the junction of the
two beds. Within a thickness of two inches the rock turns from
a Nummulitic to an Alveoline limestone (PI. 3, fig. 2). What
possible explanation can there be for such a radical and cata-
clysmic change, necessitating the practical extinction of one
dominant, and the sudden rise to prominence of another, widely
different, type? It cannot be a case of evolution, as the two
species represent entirely different types of structure.

With the passing of the Eocene period the Foraminifera lose
their all-important position as rock-builders. Through Oligocene
and Miocene times they continued to flourish, and to form
deposits largely or entirely built up of their remains. The genus
-Nummulites dies out, dies so completely that at the present day
it is represented by only a single small species of rare occurrence
in tropical seas. Alveolina persists, but no longer as a dominant.
Orbitoides, a highly specialised type which had made its first
appearance in the Chalk of Maestricht, attains sudden abundance
and forms great beds of Orbitoidal limestone in all the Con-
tinents, only to die out absolutely in the Miocene (PI. 3, fig. 3).
But the Miocene and later Tertiary deposits, though often
presenting an abundant and extremely varied foraminiferal
fauna, no longer owe their existence to the occurrence of one or
iew species in enormous numbers, except in those comparatively
few deep-sea deposits which have been raised to the surface
in the West Indies, New Guinea and the Pacific, and which
are similar in structure and often in species to the deposits
which are being found in the deep sea to-day (25) (26) (PI. 3,

&s - i] - . ....

Perhaps the conditions under which foraminiferal life exists
to-day may help to explain the change. We have now no seas
-swarming with Nummulites and Alveolina, to the practical
exclusion of other species Here and there about the world the
shallow-water Foraminifera are to be found in such .profusion
that, given favourable means of preservation, we should have in
time a true foraminiferal limestone. From the shallow waters of
the West Indian seas we have received dredgings almost entirely
composed of the genera Orbiculina and Miliolina. In the shallow
lagoons of the Pacific Tinoporus baculatus, Alveolina Boscii and

12 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA

Orbitolites complanata still form banks which impede navigation.
But speaking generally, the activity of the Foraminifera to-day
is displayed in another sphere. In the surface waters of the
great oceans the few genera which are found in the pelagic-
condition swarm in countless numbers, and their dead shells
falling constantly to the sea floor, are there building up layers of
Globigerina ooze which, if solidified and raised to the surface,,
would be visible as areas of foraminiferal limestone exceeding
even the Nummulitic limestones in extent.

Murray and Renard estimate the area of sea bottom over
which Globigerina ooze is at present in process of formation at
over 49 1 million square miles. Of its depth we can, of course,,
form no idea, but as the great oceans are practically permanent,,
it must be very great, because we know from deep-sea deposits
which have been elevated into land surfaces in Malta, Barbados,.
Trinidad and Australasia, that similar deposits have been forming
in the deep sea ever since at least Miocene times.

Prof. Agassiz has observed (29) : "No lithological distinction
of any value has been established between the chalk proper and
the calcareous mud of the Atlantic," and it has been reasonably
postulated by Prof. Jukes-Brown (30), after a careful analysis
of calcareous oozes, that the chalk was deposited in a sea of less
than 500 fathoms, though doubtless at a considerable distance
from land. The time occupied in the deposit of the English
chalk, arguing by the rate at which the Atlantic ooze is
formed, which is one foot in a century, must have been
150,000 years.

We cannot but feel that this paper has already overpassed the
reasonable limits of such a communication, but our difficulty has
been mainly one of selection. The matter is one whose ramifi-
cations are almost infinite. A systematic study of the dynamics
of the subject remains yet to be completed, though significant
beginnings have been made by Prof. Hull and by Prof. Jukes-
Brown. A careful consideration of the factors which have led
to the deposition of certain forms of Foraminifera and other
microzoa in an orderly sequence, dependent for the most part
upon current action and specific gravity, must lead us to an
understanding of the forces which have accounted for the
Building of the World in the form in which we know it. And
it is by the study* of such factors, as revealed by their results,

IN THEIR RuLE AS WORLD-BUILDERS. 13

that geologists have been able to reconstruct the geographical
features of ages inconceivably remote.

Bibliography.

1. Dawson, J. W. On the Structure of Certain Organic

Remains in the Laurentian Limestones of Canada. Quart.
Journ. Geol. Soc, 1865, p. 51, pi. vi., vii.

2. Carpenter, W. B. Additional Note on the Structure and

Affinities of Eozoon Canadense. Quart. Journ. Geol. Soc,
1865, p. 59, pi. viii., ix.

3. Ibid. On the Structure, Affinities and Geological Position of

Eozoon Canadense. Intellectual Observer, No. XI., p. 278.
2 plates.

4. Cayeux, L. Sur la Presence de Restes de Foraminiferes dans

les Terrains precambriens de Bretagne. Ann. Soc. Geol.
Xord., 1894, vol. xxii., pp. 116-19.

5. Ehrexberg, C. G. Ueber andere massenhafte mikroskopische

Lebensformen der altesten silurischen Grauwacken-Thone
bei Petersburg. Sitzungs. phys.-math. Kl. Monatsb. Ak.
Wiss., Berlin, 1858, p. 324, pi. i.

6. Matthew, W. D. On Phosphate Nodules from the Cambrian

of Southern New Brunswick. Trans. New York Acad.
Science, 1893, vol. xii., pp. 108-20 and pi. i.-iv.

7. Matthew, G. F. The Protolenus Fauna. Trans. New York

Acad. Science, 1895, vol. xiv., pp. 109-11, pi. i.
S. De Lapparent, A. Traite de Geologie, 4th ed., 1900, Paris,
p. 790.

9. Chapman, F. Foraminifera from an Upper Cambrian

Horizon in the Malverns. Quart. Journ. Geol. Soc, 1900,
pp. 257-63, pi. xv.

10. Keeping, W. On some remains of Plants, Foraminifera and

Annelida in the Silurian Rocks of Central Wales. Geo-
logical Magazine, 1882 ; Dec. II., vol ix., p. 490.

11. Blake, J. F. Lower Silurian Foraminifera. Geological

Magazine, 1876, N.S. (Dec. II.), vol. iii., p. 134.

12. Brady, H. B. Note on some Silurian Lagenae. Geological

Magazine, 1888, pp. 481-84.

13. Terquem, O. Observations sur quelques fossiles des

Epoques Primaires. Bull. Soc. Geol. France, Ser. 3 (1880),
vol. viii., pp. 414-18, and pi. xi.

14 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA

14. Chapman, F. On some Fossils of Wenlock Age from Mulde r

near Klinteberg, Gotland. Ann. Mag. Nat. Hist., 1901 r
pp. 141-60, pi. iii.

15. Vine, G. R. Notes on the Annelida tubicola of the Wenlock

Shales from the washings of Mr. G. Maw, F.G.S. Quart,
Journ. Geol. Soc, vol. 32 (1882), p. 390. See also
F. Chapman, Ann. Mag. Nat. Hist., 1895, Ser. VI.,.
vol. xvi., p. 311.

16. Chapman, F. The Foraminifera. London, 1902, p. 255.

17. Ibid. Note on the specific name of the Saccammina of the

Carboniferous Limestone. Ann. Mag. Nat. Hist., 1898,
Ser. 7, vol i., pp. 216-18.

18. Chapman, F., and Howchin, W. A monograph of the

Foraminifera of the Permo-Carboniferous Limestones of
New South Wales. Mem. Geol. Survey, New South Wales,
1905. Palaeontology, No. 14, p. 5.

19. Chapman, F. On some Foraminifera of Rhaetic Age from

Wedmore, in Somerset. Ann. Mag. Nat. Hist., 1895 r
Ser. 6, vol. xvi., pp. 305-29, 2 plates.

20. Haeusler, P. Die Astrorhiziden und Lituoliden der

Bimammatus-zone. Neues Jahrb. filr Min., 1883, vol. i. r
pp. 55-61, pi. iii., iv.

21. Ibid. Monographie der Foraminiferen der Transversarius-

Zone. Abhandl. Schiveiz. Paldont. Gesellsch., 1891,,
vol. xvii., pp. 1-135, 15 plates.

22. Mobius, K. Der Bau der Eozoon Canadense nach einigen

Untersuchungen vergleichen mit dem Bau der Foramini-
feren. Cassel, 1878.

23. Heron-Allen, E. Prolegomena towards the study of the

Chalk Foraminifera. London, 1894, pp. 10-14.

24. Heron-Allen, E., and Earland, A. The Recent and Fossil

Foraminifera of the Shore-sands at Selsey Bill, Sussex.
Journ. R. Micr. Soc, 1908, p. 529; 1909, pp. 306, 422 r
677 ; 1910, pp. 401, 693 ; 1911, pp. 298, 436.

25. Schubert, P. Die fossilen Foraminiferen der Bismarck-

archipels und einiger angrenzender Inseln. K. K. Geo-
logischen lieichsanstalt, vol. xx. Part 4. Vienna, 1911.

26. Jukes-Brown, A. J., and Harrison, J. B. The Geology of

Barbados. Part II. The Oceanic Deposits. Quart.
Joarn. Geol. Soc, 1892, vol 48, p. 170.

IN THEIR ROLE AS WORLD-BUILDERS. 15

27. La Harpe, P. de. Monographie der in Aegypten und der

libyschen Wiiste vorkommenden Nummuliten. Palaeonto-
graphica, vol. xxx. 1883 (3 Folge, Bd. 36), p. 155.

28. Carpenter, W. B., Parker, W. K., Jones, T. B. Intro-

duction to the study of the Foraminifera. London (Ray
Soc), 1852, p. 262.

29. Agassiz, A. Three Cruises of the Blake. London, 1888,.

vol. i., p. 150.

30. Jukes-Brown, A. J. Handbook of Physical Geology.

London, 1884, p. 130.

31. Haug, E. Traitede Geologic II. Les Periodes Geologiques.

Fascicule 3. Paris, 1911.

32. Jukes-Brown, A. J. The Cretaceous Bocks of Britain, with

contributions by W. Hill. London, Geological Survey,
volii., 1903, vol. iii., 1904.

Description of Plates 1 3.

With the exception of PI. 1, fig. 1, PI. 3, fig. 4, the figures are
from original sources.

Plate 1.

Fig. 1. Spirillina Limestone. Upper Cambrian, Malvern (after
Chapman, Q.J.G.S., vol. lvi., 1900, Plate 15).

,, 2. Saccammina Limestone. Carboniferous. Pathhead, Had-
dington, N.B.

,, 3. Endothyra Limestone. Carboniferous. Indiana.

4. Nubecularia Limestone. Permo- carboniferous. Polkolbin,
Maitland, N. S. Wales.

Plate 2.

Fig. 1. Middle Chalk. Zone of Rhynchonella Cuvieri. Hitchin.
,, 2. Alveolina Limestone. Eocene. Mixon Bock, Selsey.
,, 3. Alveolina Limestone. Eocene. Bunnu, N. W. Frontier

India.
, 4. Kummulitic Limestone. Eocene. Gizehj Egypt.

16 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA.

Plate 3.

Fig. 1. Nummulites Gizehensis (Ehrenberg), microspheric speci-
men. Horizontal section, through primordial chamber.
2. Alveolina and Nummulitic Limestone. Eocene. Shiranni,
N. W. Frontier, India, showing the junction of the
two beds.

3. Orbitoidal Limestone. Miocene. Japan.

4. Globigerina Limestone. Miocene. Bismarck Archipelago,
Pacific (after Schubert, loc. cit., Plate 5, fig. 4).

Jourii. Quekett MicroscopicabClub, Ser. 2, Vol. XIL, No. 72, April 1913.

Journ. Q.M.C.

Ser. 2, Vol. XII., PI. 1

3 4

Fo RAM IN I FERAL LIMESTONES.

Journ. Q.M.C.

Ser. 2, Vol. XII., PI. 2.

FoRAMINIFERAL LIMESTONES.

Journ. Q.M.C.

Ser. 2, Vol. XIL, PL 3.

3 4

FORAMINIFERAL LIMESTONES.

17

NOTES ON SOME OF THE DISCOID DIATOMS.

By W. M. Bale, F.R.M.S.

(Contributed by Prof. A. Bendy, January 2Sth, 1913.)

In the following notes, written for the most part several years
since, I have attempted, in somewhat desultory fashion, a survey
of some of the principal characters which have been utilised in
the discrimination of species in three or four of the best-known
genera of discoid diatoms. Some of the conclusions at which I
have arrived as to the inadequacy of many of these distinctions
have, I am aware, been reached by previous observers, more
especially in the genus Coscinodiscus ; but in such cases the
special instances now brought forward may perhaps be service-
able in reinforcing those conclusions. In other cases, particularly
in the genus Actinoptychus, my observations tend to prove that
characters accepted as specific even by recent authors are de-
monstrably unreliable. I have not pursued my investigations
more fully, as I have found the subject too difficult, owing to the
impossibility of procuring much of the literature, and to my total
isolation from other observers. I trust, however, that these notes
may not be without interest for students of the Diatomaceae,
and that the suggestions therein may be of some value to those
who occupy themselves with their classification.

Coscinodiscus. Notwithstanding all that has been done to-
wards the elucidation of this unwieldy genus, it still remains the
most difficult as it is the most extensive of the whole order.
This follows naturally from the general similarity of form, and
the absence in most cases of any specialised areas or conspicuous
appendages such as serve to distinguish the species in Actin-
cptychus, A uliscus, etc. Many forms which have been described as

Journ. Q. M. C, Series II. No. 72. 2

18 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

distinct differ only in having the markings a little smaller or
larger, while others are characterised by trifling distinctions of
detail which, on examination of an extended series of specimens,
are found to break down utterly. On the other hand it will be
seen that, in many instances, details which might be helpful in
the discrimination of species have been generally overlooked.

The first serious attempt to grapple with the difficulties
involved in the classification of the genus was that of Grunow,.
in his work on the Diatoms of Franz-Josef Land, a perusal of
which leads one to regret that this acute observer did not carry
out a more comprehensive survey of the whole genus. Rattray's
Revision, though giving evidence of a vast amount of painstaking
research, is far from final in regard to the species admitted,
many of which are characterised by features obviously not of
specific sometimes not even of varietal value. Moreover, in
working over slides from well-known deposits, one finds many
forms which it is impossible to place under any of the species
described, though it is most unlikely that Rattray could have
failed to observe them. The impression is produced that many
of the descriptions have been framed on particular specimens,,
without any allowance for the range of variation usually present.
The "key" is minimised in value owing to the use in many of
the sections of characters which are quite inconstant, or which
may characterise the type but not the varieties, while the attempt
to include all the sections in one key has added much to the
difficulty of the undertaking, and has involved mistakes which
render it in some cases quite unreliable. (As an example, let
the observer take a typical valve of C. asteromphalus and attempt-
to trace it through the key, and he will fail to find it. But it
appears under Section 116, and, if followed backwards, it will
be referred to Section 111, where the description is, "Markings
rounded, granular ; interspaces hyaline, unequal, rows radial,"
which obviously cannot apply to the species at all.)

Nevertheless Rattray's work undoubtedly represents a great
advance in its suppression of a large number of pseudo-species,
though one cannot but regret that the process has not been
carried further.

Mr. Cox, going to the opposite extreme, would reduce all the
multitudinous forms of Coscinodiscus to seven species, Actinocyclus
Ehrenbergii being included as one of them. Some diatomists

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 19

have expressed approval of this proposal, but none have adopted
it, nor are any likely to do so.

In surveying the various characters by which species may be
defined, the outline will naturally be the first to be considered.
This in the Coscinodisci, however, is of little assistance, as, except
in a few aberrant species, the circular form prevails. Passing to
the surface contour, we have a character which has been utilised
by Grunow, Rattray, and others, but by no means so fully as
might be. Thus neither of these observers, in differentiating
C. asteromphalus from C. centralis, refers to the fact that the
former has usually the centre depressed, while the latter is
convex throughout. In several cases the absence of information
on this point in Rattray's descriptions just renders the diagnosis
doubtful. And this is the more important from the fact that
even a good figure does not always bring out this special point.
At the same time it may be observed that it is not rare for
individuals of a given species to depart from the normal character
in regard to surface contour, and further, that in particular
localities this variation may prevail. This refers especially to a
tendency for the surface to be more depressed than is normally
the case, and does not apply to C oscinodiscus only. Thus in some
of the Oamaru deposits we find that Aulacodiscus margaritaceus,
A. amoenus and the large forms of the Triceratium favus group
are all characterised by the unusually depressed surface of the
valves.

It may be noted, further, that it is not safe to describe the
surface contour of a species without examining both valves.
Rattray describes C. superbus as convex, but in reality one valve
is convex, while the other has the centre depressed. Several
species, such as C. tumidus, have the surface concentrically undu-
lated, while in a series of forms, described by Grunow as Pseudo-
Stephanodiscus, there is an asymmetrical inflation of the surface.
The inflations and depressions in C. excavatus are also familiar
examples of specialised areas.

Variations of the radial symmetry, other than those men-
tioned, are rare. A notable instance is that of C. cocconeiformis,
which has the markings bilaterally arranged.

In the great majority of cases the form, size and arrangement
of the cellules or puncta which cover the surface are the prin-
cipal or sole ground relied upon for specific distinction, many

20 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

so-called species being differentiated solely by slight variations in
the size of the areolation, or by its increasing or decreasing
in size towards the margin. All such species, unless other and
weightier differences can be found, should be swept aside as
spurious. The same remark applies to the presence or absence
of a central area, of a central rosette of larger areolae, of
bright points at the origin of the shorter radial series, of parts
of the surface where the polygonal areolation is replaced by
separate circular cellules, and of fine punctate secondary markings.
Any of these characters may, of course, be constantly associated
with a particular species; but, in many species at any rate,
examination of a sufficient series readily shows that they may be
indifferently present or not. Indeed, within the limits of the
single species C. asteromphalus a range of forms may be found
some or other of which exhibit every one of the characters just
mentioned, while others show none of them.

In some respects the size of the valve (i.e. with reference to
the average of the species) is a determining factor in the
arrangement of the markings. Thus in such forms of C. radiatus
as are usually considered typical there are commonly three or
four slightly larger cellules in the centre, and the rest are in
distinctly radial series. In smaller valves the central cellules
are no longer than the rest, and in the smallest forms the radial
disposition of the cellules is totally lost. A still more striking
instance is found in one of the robust forms of C. asteromphalus,
common in some of the North American deposits. The largest
valves have a conspicuous central rosette of large cellules, and
outside these the areolae are much smaller, gradually increasing
in size, however, to the mid-radius. With a diminution in the
size of the valve comes a modification in the direction of levelling
down the differences in size of the areolation the rosette-cells
become smaller, and those next to them larger in proportion.
One stage in this series is the C. biangulatus of Schmidt, which
is only a normal form of this group, and by no means of specific
or even varietal value. In the smallest forms of the series all
trace of the rosette is wanting, the areolae are fairly uniform in
size throughout, and the centre of the valve is not depressed as
in larger specimens, but convex or very slightly flattened, while
in many valves the cellules are separate and circular on part of
the surface, as in C. perforatus and C. apiculatus. Similarly the

-I

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 21

C. crassus, so abundant in the Sendai deposit, simply consists of
the smaller valves of the equally abundant G. borealis, to which
it bears the same relationship that C. biangulatus does to
C. asteromphalus.

In C. marginatus the small valves, with uniform and non-
radial areolation, are considered typical, but, as in the above-
mentioned species, we find that valves of maximum size have the
areolation distinctly radial, with the areolae increasing in size
from the central rosette towards the margin.

In other species similar conditions occur, indicating that the
reduction of the differences in size of the areolae is the regular
concomitant of the reduction in size of the valves, and showing
how little such variations are to be relied on as specific
distinctions.

The presence of a central area may be of specific value in
some instances, but in many species it is quite worthless even as
a varietal character. Sometimes its disappearance is due to the
cellules surrounding it becoming enlarged at its expense. Thus
in C. perforatus and C. apiculatus normal valves (if indeed wo
are right in considering as normal those valves with separate
round markings, which I greatly doubt) have a blank central
space, and the cellules surrounding it are in no way different
from the rest, but when, by the enlarging of the cellules-
generally at the expense of the intervening substance, the
structure becomes areolate, the most central cellules often
enlarge inwards till they obliterate the area, and thus form a
rosette, as in C. Oculus Iridis, etc.

Far too much importance has been attached to the area in
Rattray's monograph, especially in the key.

The central rosette is one of the most variable of characters.
In some cases, as already mentioned, it is conspicuous in the
largest valves, dwindling and finally vanishing in the smaller
ones ; in others, just alluded to, it results from the obliteration,
entire or partial, of the central area. In some no doubt it
may be regarded as a fairly constant specific character.

The tendency in some species for the polygonal areolation to
be replaced on a portion of the valve by isolated circular cellules
may be briefly referred to. C. perforatus and C. apiculatus are
familiar cases in which this modification occurs, either over the
whole surface of the valve, or on more or less of one side, while

22 W. M. BALE ON .SOME OF THE DISCOID DIATOMS.

in C. gigas, G. diorama, and a few others, it is the central part
of the valve which is so modified. Though in C. apiculatus and
C. perforat us it is universally recognised that this peculiarity is
not of specific importance, the loose disposition of the markings
in the central part of such species as C. diorama has been made
use of to characterise the species, but in some cases at least
unwarrantably. In a species found in Port Phillip the larger
valves have the markings as in G. diorama, while the smaller
ones are areolate throughout. When the modification in question
occurs in the central part of a valve it is usually associated with
a thinner condition of the silex, but this does not appear to be
the case in such species as G. perforatus and G. apiculatus.

In rare cases the loosely disposed and rounded markings occur
on an annular area, concentric with the margin, and an interest-
ing example of this is found in the large, robust form of G. Oculus
Iridis found in the Mors deposit. It is a variable form as regards
the surface contour, but commonly in large valves the centre and
the sub-marginal zone are about equally elevated, and the inter-
vening broad annular area is slightly depressed. A varietal
form differs in having this depression much deeper, and, on the
outer side, very abrupt, while in a third form the annular
depression is very deep and narrow, and on the bottom of the
depression the cellules are rounded and separate (a condition to
which there is sometimes a tendency in the second form). This
last variety was described by Grunow in his work on the diatoms
of Franz-Josef Land as a new species, under the name of
G. annidatus, notwithstanding which it was figured later on
PI. 184 of Schmidt's Atlas under the name of Craspedodiscus
Molleri.

I have also seen a form of G. excavatus, very near to Grunow' s
var. semilunaris, in which there is a complete annular depression,
with round markings, not far from the centre.

The circular areas of the varieties just mentioned, as well as
the inflations of ordinary forms of G. excavatus, are all instances
of abrupt bulging in (or out) of the substance of the valve, and
in all of them the portion which is subject to this bulging
appears thinner than the rest of the valve, while the markings
are fainter, as well as being rounded and loosely disposed.

The occurrence of " bright points " at the origin of the shorter
radial series of cellules has been commonly regarded as a valid

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 23

specific character. In some instances these " bright points " are
merely the optical expression of a local thickening of the silex ;
more generally, however, they are true cellules, differing from the
rest in their minute size. They are conspicuous in C. perforatus,
and they form the principal ground of distinction between that
species and C. apiculatus. But in examining a large series of
. perforatus var. ceilulosa I find them by no means so constant
as to justify the importance attached to them. While in some
valves they appear at the origin of all, or nearly all, the shorter
rows of areolae, in others they are much sparser, and in a few
cases I failed to detect more than four or five on the whole valve.
In such cases, and when, as often happens, the central area is
obsolete, it is a critical matter indeed to distinguish the valve
from C. radiatus, and in passing I may note that the " C. radiatus"
of my Holler's Typen-Platte is just one of these valves of
C. perforatus var. ceilulosa, with all its bright points complete.
C. obscurus may be mentioned as another species in which the
bright points, usually present, may be either totally absent or
reduced to a very small number. On the other hand the points
often occur in species which are normally without them. I have
met with instances of this kind in C. aster omphalus, on a narrow
unilateral area where the cellules are separate and rounded. In
a slide from Cambridge, Barbados, there are numerous valves of
C. excavatus, most of which display these minute cellules, and in
some valves not only at the origin of the radial series, but
profusely interspersed among the large areolae all over the
surface, even in places other than the angles of the areolae. And
I have a curious valve of Endyctia oceanica, in which these
minute cellules form the principal part of the areolation, the
ordinary large cells only existing in scattered groups of four or
five, surrounded on all sides by the network of small ones.

I have referred already to the small importance to be attached
to mere differences in the size of the areolation, but I would
further remark that it must by no means be assumed that only
small differences are to be disregarded. Valves of C. concinnus
may have only four cellules in 0*01 mm., while others may have
as many as twelve, though the valve may be much larger. And
I have seen a frustule of C. excentricus in which one valve was
twice as finely marked as the other. Such instances show forcibly
the futility of distinctions founded on the size of the areolation.

24 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

\

The structure of the valve-border is a feature which has not
always received sufficient attention from observers, who have
overlooked peculiarities which might be of service in classification.
This refers to the general character of the border, and more
particularly to the minute appendages which it frequently bears.
The apiculi which form a circlet at the margin of many species
are familiar to all observers, more especially those which in some
of the Fasciculati and Cestodiscoidales attain a prominence which
could not fail to attract attention. But those which are
asymmetrical, and of which only one or two appear on each valve,
have hitherto singularly escaped notice, except in a very few
instances, where they are more conspicuous than usual. For
example, in the robust form of C. lineatus, described as C. leptopus,
a single larger apiculus, farther in than the rest, is quoted by
Rattray as distinguishing C. leptopus from its allies. Y~et in
fact it is not peculiar to this form, a similar apiculus, but more
delicate, being easily discoverable in other and more nearly
typical forms of C. lineatus. Further, it is equally a feature of
C. excentricus, and I find it commonly present, though apparently
hitherto unnoticed, in forms of that species from such different
localities as Port Phillip, Cuxhaven, Santa Monica, and Peru and
Bolivia guanos. (There is, of course, no justification for the line
of demarcation drawn by Battray between the respective groups
of the Lineati and the Excentrici. The two type species are con-
nected by intermediate forms, and the same remark applies to
C. excentricus and C. subtilis.)

Among the Badiati the tendency is towards the production of
two apiculi, which occupy positions about one-third or one-fourth
of the circumference apart. They are found in many species,,
though strangely enough I can find no mention of them by any
observer except in the cases of G. concinnus and C. centralis, in
both of which forms they are very conspicuous. Battray says
that C. centralis is distinguished from C. asteromphalus by these
apiculi, and cannot be united with it in the same species, as pro-
posed by Grunow. An unfortunate dictum, since all, or nearly
all, of the numerous varieties of C. asteromphalus agree precisely
with C. centralis in this respect, while such apiculi, but more
rudimentary and indefinite, are found in a wide range of forms
comprised under C. marginatus, C. perforates, C. apiculatus r
C. borealis and others. Their minute size and indefinite form

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 25-

cause them to be easily overlooked against the coarsely marked
background of the valve-areolation, but in C. concinnus and
G. centralis they are more conspicuous, owing largely to the more
delicate and transparent condition of the valve.

The key to the position of these apiculi is, however, to be found
in certain modifications of the valve-border which occur in the
vicinity, and which indeed are often obvious when it is difficult
or impossible to detect the apiculi themselves. These modifications
may take the form of a thinning away of the valve-surface (C.
marginatus), or an apparent notching of the margin (C. borealis,
C. diorama, etc.), or a sinuation of the inner edge of the thickened
border (G. aster omphalus) . In the last species this marginal
structure is very conspicuous, at least in the robust valves, and it
is shown in Schmidt's figures of C. biangulatus and one or two
others.

In C. perforatus and C. apiculatus (at least in the areolate
forms) two minute notches in the extreme margin of the areo-
lation can in most cases be seen, and by careful examination the
apiculi may generally be found opposite them, but they appear
no more than a slight thickening of the silex, w T hich would
certainly never be noticed except for the marginal clue. In
C. marginatus the coarse radial structure of the marginal zone is
thinned away over two comparatively large areas, sometimes very
noticeably, but the apiculi themselves are difficult to make out.

The apiculi are most fully developed in C. centralis and C.
aster omiAalus. They are best seen by examining the inside of
a large valve in which the marginal part is steeply convex, so
that the apiculi, which project into the valve a little above the
rim, can be observed without the interference of an immediate
background. The apiculus takes the form of a minute disc,
attached by a central point, and bearing a sub-globular or irregular
mass. The border in C. asteromphalus is usually widened in-
wardly so as to form an annular projection into the cavity of
the frustule. The extent to which this widening takes place
varies greatly, even in the same variety ; but whatever its width,
so long as it projects inwards at all, it is sinuated under the
apiculi, which are always uncovered, so that the sinuations are
deeper as the valve-border is wider. The structure would seem
to imply the presence in the living organism of some direct
communicating filaments between the apiculi of the two valves,

) W. M. BALE ON SOME OF THE DISCOID DIATOMS.

on which the inward extension of the border must never encroach.
I have had no opportunity of proving whether this is so, or even
o: ascertaining whether the apiculi of the two valves are opposite,
except in a single instance a large cylindrical frustule of C.
mirificus mounted in zonal view, and in this the apiculi are
opposite.

In C. gigas the apiculi are, if present, obscure, and I can find
no marginal indications of them. C. diorama and allied forms,
however, often classed as varieties of C. gigas, have the border
distinctly marked with two apparent notches as in C. perforatus.
C concinnus has distinct apiculi, and many specimens have in
addition crescentic processes outside the valve, partly surrounding
the point at which the apiculi originate. These valves are known
as Eupodiscus Jonesianus Greville (E. commutatus Grunow), but
I do not think they have any claim to rank even as a variety.
They are abundant in slides from Ouxhaven, mixed indis-
criminately with valves having the internal apiculi only.

While several forms besides those which I can identify with
the foregoing species share in the peculiarity in question, there
are many others in which I have failed to detect it. Such are the
thick variety of C. Oculus Iridis found in the Mors deposit, also
C. radiatus. In more typical forms of C . Oculus Iridis, however,
careful search has disclosed two apiculi, which are simple bacillar
projections into the cavity of the frustule.

Apart from these appendages the structure of the border itself
has in many cases not received sufficient attention as a help in
classification. Some species have distinct borders with markings
quite different from those of the valve generally, others have the
areolar structure continued to the extreme margin without
interruption ; in some the edge is turned over, in others it is
quite flat, and frequently the specific diagnosis contains no
hint of the character of the valve in this respect ; so that of two
valves, differing widely in this particular, it may be impossible to
decide which of them corresponds with the specific description.
C. concinnus and C. centralis may serve to illustrate this. Both
are very convex, but in the former the marginal part is slightly
flattened, the areolae diminish to a very minute size, and are
succeeded by an extremely narrow hyaline border, thinning
away so as to show only a smooth single contour. In a typical
C. centralis, on the other hand, the valve curves downward to the

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 27

extreme edge, and the areolae are of an appreciable size throughout,
while the border is not thinned away, so that on focusing the
margin there is visible a distinct double contour, with the walls of
the last row of cellules showing as coarse transverse striae.

Several species exhibit a tendency for the border to become
wider in proportion as the valves are smaller. C. obscurus and
V. apiculatus are instances of this. In both these species I have
traced a series down to forms with wide borders, which are
only to be distinguished with difficulty from C. marginatus.
In Nottingham and other American deposits such forms of
C apiculatus are common, and one of them figured by Schmidt
(PI. 62, f. 11, 12) has been referred by Rattray to C. marginatus.

In several species of the Radiati the angles of the areolae often
tend to become thickened, so that in a certain focus there appears
to be a bead at each angle. This feature has no specific im-
portance, and I agree with Rattray that the presence at each
a,ngle of a distinct spine, as occasionally found, is of no greater
consequence.

I have already referred to the close affinity which exists
between the Excentrici and the Fasciculati, e.g. between C. ex-
centricus and C. subtilis. Grunow mentioned this affinity, but
Rattray says that it is remote. Grunow's view is undoubtedly
correct. In a typical G. excentricus there is a central cellule,
and surrounding it a circle, generally of seven. Each of these
seven is the centre of an arcuate line of cellules, extending to
the margin on either side, behind which is a succession of similar
arcuate series, so that the whole of the cellules may be regarded
as forming seven fascicles, crossing each other symmetrically, so
that no division-lines exist, and for the most part each cellule
will form part of three different fascicles. In C. subtilis and
C. symbolophorus the number of fascicles is greater, and the
divisions between them more abrupt, especially in the central
part of the valve, so that the fasciculation is more manifest, but
even in these forms the fascicles blend towards the margin in the
same way as those of C. excentricus. I have seen a frustule of
the latter species in which one valve was normal, while the
other was far more finely marked, and was as distinctly
fasciculate as C. subtilis.

I should mention that the C. subtilis referred to is Grunow'
typical form, which is quite different from Rattray's, though

W. M. BALE ON SOME OF THE DISCOID DIATOMS.

that observer quotes Grunovv as his authority. He describes
C. subtilis as apiculate, and differentiates other species from it
by the absence of apiculi. Yet Grunow says expressly that
C. subtilis is non-apiculate. " Der Ausgangspunkt fiir alle diese
Formen ist der stachellose C. subtilis (Ehr. partim), Gregory,
Grunow " (Diat., F.-Josef Land, p. 81). This form, which is similar
to C. symbolophorus, but without the stellate markings at the
centre, also agrees well with Rattray's own account of Ehren-
berg's original species. It is not common, and Yan Heurck
figures it from guano, not finding it in European gatherings.
But Peragallo, like Rattray, though claiming to follow Grunow's
authority for the type, has figured and described a totally different
form an apiculate variety.

Actinocyclus. The excessive multiplication of specific names
which encumbers the Coscinodisci has not been carried out to a
corresponding extent in the much smaller group of the Actino-
cycli (ignoring, of course, Ehrenberg's multitudinous pseudo-
species) ; still there is no doubt that an undue regard for certain
points of structure has led to the establishment of several species
on insufficient grounds. Rattray's monograph admits about
seventy species : Fome of these have no claim to recognition, but,
on the other hand, I find that about fifteen out of thirty-four
species or varieties which I possess cannot be identified with any
of Rattray's descriptions. He has adopted in this monograph
the plan of furnishing extremely long and minutely detailed
descriptions, a method which renders identification more certain
when one is dealing with the precise form described, but does
not allow for the variations which constantly present themselves
even in a single gathering. In fact, as I have remarked in
reference to Coscinocliscus, many of these are not descriptions
of species, but of individual diatoms. Mr. Rattray uses five
places of decimals to express the fraction of a millimetre which
corresponds to the diameter of a pseudo-nodule ! Of what
possible use can such measurements be when applied to structures
so notoriously variable ?

Before discussing the range of variation in the genus, and
as I shall refer repeatedly to the commonest species A. Ehren-
bergii I must premise that I use that name in the sense in
which it is used by Ralfs himself, and by Yan Heurck, Grunow,
Peragallo, and, so far as I know, by all other observers except

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 29

Rattray, who has unaccountably assigned the name to an entirely
different form, while describing the true A. Ehrenbergii as
A. moniliformis Ralfs. A. Ehrenbergii was described by Ralfs
from his own knowledge, while A. moniliformis was merely a
name given by him to certain forms from Oran and Virginia,
which he had not seen, but which he judged from Ehrenberg's
tigures to be distinct, the distinction consisting in the division
of A. Ehrenbergii into compartments by double lines, while
A. moniliformis was divided by single ones. There is really no
difference, except such as depends on the size of the valves and
the number of the fasciculi. In small valves, containing few
fascicles, the interfasciculate rays form a wide angle with the
other series, and are therefore very marked ; and these are the
" single series of dots " referred to by Ralfs. In large valves
the fascicles are numerous and narrow, so the interfasciculate
rays form a small angle with the other series, which, stopping
short at various points, leave a double row of subulate blank
spaces along the sides of each primary or interfasciculate ray,
and 'these subulate areas constitute the "double lines" of Ralfs.
That the small valves from Oran and Virginia, and the large
ones from Cuxhaven, etc., are one and the same species is fully
recognised, however, by Rattray, but he names them A. monili-
formis. To any one who reads carefully Ralfs' account of
A. Ehrenbergii there can be no possible doubt as to the identity
of the species. It was established specially to include the
many-rayed forms described by Ehrenberg, which mostly occur
at Cuxhaven ; Ralfs also states that it is " very fine in Ichaboe
guano," and that most of the forms can be obtained therein ;
and further, that it is " common, both recent and fossil." One
species, and only one, answers perfectly to this description,
namely, that which Rattray calls A. moniliformis, but which,
in its larger forms, at least, has been recognised by observers
generally as A. Ehrenbergii. Rattray might have been justified
in preferring the name of A. moniliformis on the ground of
priority, but he has failed to perceive that the forms which he
has placed under it are no other than the A. Ehrenbergii of
authors, and has inexplicably assigned the name A. Ehrenbergii
to a species (or variety) differing entirely from that described
by Ralfs. It is not found at Cuxhaven, nor, so far as is known,
in Europe at all ; it is far from being common, either recent

30 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

or fossil, and it is not found in Ichaboe guano. It is dis-
tinguished from the true A. Ehrenbergii by its concentrically
undulated valves, by its strong iridescence, and by its sharply
defined zones of colour under low powers. Its granules are
also more closely and regularly arranged, forming over the
greater part of the valve a very regular areolation. To
distinguish it from the true A. Ehrenbergii I propose for it
the specific name of A. rex. I have only found it in the
deposits of Nottingham, Curfield, Atlantic City, and Lyons
Creek. Rattray's localities are necessarily unreliable, so far
as they are given on the authority of other observers, of whom
some at least (Ralfs, for example) were referring to the true
A. Ehrenbergii, and not this form at all.

Rattray's description of this species, however, requires amend-
ment, especially as regards the contour of the valve. He says-
that large valves have the centre depressed, and two concentric
elevated zones between the centre and the border, while small
valves have the centre depressed, and are convex between it and
the border. This is correct so far as some of the valves are
concerned, but in others the surface elevations and depressions
are in the opposite order. Thus in large valves the centre is
convex, and there is one elevated zone between it and the border^
Evidently the frustule is concentrically undulated as a whole,
the depressions of one valve corresponding to the elevations of
the other. So in the case of the small valves with depressed
centre, others, evidently their counterparts, have the centre
convex. Some of the valves in my slides are 0*20 mm. in diameter,
Rattray's maximum being 0*17.

The largest European species is, according to Rattray, A.Ralfsii r
of which I have not seen specimens agreeing entirely with
Peragallo's description of the type ; but among the forms of
A. Ehrenbergii abundant in slides from Cuxhaven and Ichaboe
guano are many which agree with that description in the
arrangement of the fasciculi and subulate areas, though not in
the brilliant appearance, the very large pseudo-nodule, nor the
concentric arrangement of the granules. One has only to read
the descriptions of Ralfs, Yan Heurck, Rattray and Peragallo
to see that no two of these observers agree as to the respective
characters of A. Ralfsii and A. Ehrenbergii, which is nob sur-
prising if, as Peragallo states, every intermediate gradation

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 31

exists between the two types. This agrees with the views
expressed by Grunow, Lagerstedt, and others ; it would seem,
therefore, that Peragallo is justified in treating A. Ehrenbergii
as at most a variety of A. Ralfsii.

Most species of A.ctinocyclus have the markings arranged on
the same general plan as A. Ehrenbergii. The surface of the
valve is divided into cuneate areas by a number of moniliform
series of granules (the interfasciculate rays), which radiate from
the centre, or near it, to the marginal zone. Each cuneate area
contains a fascicle of similar moniliform series, but only the
central one is strictly radial, and all the others are parallel
with it ; and as they all stop short of the interfasciculate rays
they are necessarily shorter as they approach these rays. The
great difference in the aspect of the valves dependent on the
small or large number of fascicles has already been mentioned.
In the largest valves, where they are most numerous, they are
so narrow that they consist of very few series of granules, and
the angles which they form with the interfasciculate rays are so-
small that at first sight it might appear that all the series are
truly radial. Such is the structure in the largest valves of
A. Ralfsii, A. Ehrenbergii, A. Barklyi, etc., but the markings are
just as truly fasciculate as in the smallest form's, though the
fasciculi are not so patent. No amount of variation of the
kind described, therefore, is in itself of importance in classification.
But great irregularities in the arrangement of the markings
prevail, and there is' perhaps no other genus in which valves
of one and the same species present such different aspects.
While one valve may have the interfasciculate rays very distinct,
all starting from a circular central ring of granules, and all the
series well defined, the next may present at first sight a very
different aspect, owing to the denseness of the granulation, and
in yet another much of the appearance of regularity may be
lost owing to its sparseness. This is especially noticeable in the
centre of the valve, where there may be a regular area, with
perhaps a few granules in the centre, while in other cases there
may be no definite area at all. Usually the interfasciculate rays
stop short at a little distance from the centre, but in the small
valves of A. Ehrenbergii from Oran, as Mr. Rattray points out,
they cross each other. Another point of variation is the width
of the blank areas along the sides of the interfasciculate rays.

32 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

Jl, fasciculatus Castracane is distinguished by the notable width
of these areas, but the character is of no specific importance.
A, Ehrenbergii often exhibits such areas, and I have seen them
in one valve while the other in the same frustule showed
scarcely a trace of them. They may even exist on only a part
of a valve. So far as Castracane's figures show, there is nothing
to distinguish his species from A. Ehrenbergii.

A frequent phenomenon in the genus is the occurrence of
regular or irregular blank areas crossing the rows of puncta,
often in a sub-concentric fashion, and A. crassus is a form in
which the apparent irregularity of the markings from this cause
has been made a ground for specific distinction. Yet both Van
Heurck and Peragallo, who admit the species, show by their
figures that the markings are as in A . Ehrenbergii, except in so
far as the granules ard obliterated over certain irregularly sub-
concentric areas. I find nothing here to warrant the separation
of the form as a distinct species.

The interfasciculate rays are also liable to interruptions, and
Castracane has described a species A. complanatus in which
they are said to be wanting, though the valve is of the ordinary
fasciculate type. I greatly doubt the correctness of this, not
merely on a priori grounds, but owing to Rattray's identification
of this species with the form distributed by Moller as A. Ralfsii.
Now the " A. Ralfsii 1 ' of my Typen-Platte is simply one of the
forms of A. Ehrenbergii in which the fasciculation is similar to
that of A. Ralfsii, and which abound in Cuxhaven and Ichaboe
guano material. The interfasciculate rays are certainly not
wanting, though doubtless obscure and irregular in parts. Many
otherwise similar valves occur in which there is no noticeable
irregularity of these rays.

The general aspect of the valve depends largely on the position
and distance of the granules relatively to the others in the same
und adjacent rows of the fascicle. In A. Barklyi the granules of
each row are very close to each other, but not so close to those
of the next rows ; the rows therefore remain distinct from each
other even to the border. In A. Ralfsii type and var. sparsus
the granules of adjacent rows are mostly side by side, so that
they form straight lines crossing the fascicles, thus having as a
whole a sub-concentric disposition ; they are also distinctly
separated from each other. In A. Ehrenbergii there is much

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 33

variation, the granules often forming irregular zigzag lines
crossing the fascicles; generally, however, the tendency is for
the granules of adjacent series to alternate with each other, and
also to be somewhat crowded, so as to form a quincuncial
arrangement, which in any case prevails towards the border.
In A. rex the alternate arrangement is much more pronounced,
and as the granules are crowded equally all round the markings
form a very regular areolation over the greater part of the
valve.

The appearance of the granules themselves varies remarkably
in the same species. In A. Ehrenbergii some valves show them
in the best focus as minute, dark, sharply defined circles, while in
others they are more pearly, and show, much more readily, a
central black spot. When crowded, especially towards the
border, they form a distinct areolation. In A. rex the latter
type predominates, but near the centre the granules are more
pearly. In A. Barklyi and A. ellipticus they vary much as
in A. Ehrenbergii. And in all these species they appear some-
times as dark, well-defined puncta. Peragallo has figured a form
which he calls A. nebulosus, and which is practically a hyaline
valve of A. Ehrenbergii with fine puncta instead of granules, also
a corresponding form with the puncta arranged like the granules
of a typical A. Ralfsii. He thinks these valves are probably the
result of cleavage, of the correctness of which opinion I think
there can be no doubt. Corresponding forms of A. Barklyi are
found in hundreds in slides of that species, often so delicate and
colourless that they become invisible on a slight alteration of the
focus. How many layers has a valve of A. Barklyi% When
manipulating one under the microscope I saw it divide into
three, one extremely thin and hyaline, and another somewhat
thicker, but still less robust than the main disc. Here the
question of colour comes in for consideration, for it is probable
that the colour as well as the appearance of the granules depends
more or less on the " state " of the valve whether it consists of
more than one plate for instance, or whether the two plates
include a film of air between them. A. rex is the most brightly
coloured form I have seen, having the colours in sharply defined
zones. A. Ehrenbergii is usually blue, green, purple, or brown,
often showing more than one colour, but not in sharp zones. A .
Barklyi varies much in the same way, but is exceptionally liable
Journ. Q. M. 0., Series II. No. 72. 3

34 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

to exhibit a dark, semi-opaque aspect. But all these species
usually include forms of the same size, contour and arrangement
of markings, but of a soft brown colour, uniform throughout
or nearly so, and generally with fine punct'a. Are these complete
valves, or secondary plates, or primary plates from which the
secondary ones have been detached ? Some of these brown discs
have the silex of the subulate areas so thickened as to appear
black under a low power. Valves of A. Ehrenbergii with
sharply defined granules and clear, distinct subulate areas mostly
appear blue under low powers, with the subulate spaces white.
Others, such as that described above, from Holler's Typen-Platte,
are more commonly green or purple, and show no white streaks,
though having large subulate areas, the substance of the valve
itself appearing to have a dusky tint. The bright colours of
these species can only be seen when dry or mounted in balsam
or a similar medium, while in water they are colourless.

No other diatom known to me presents such endless variety
of marking as A. Barklyi, and occurring, as it does, in such
profusion, it is especially suitable for a study in variation. This
diatom is of interest as being probably the first to be named in
Australia, it having been described by Dr. Coates in the Trans-
actions of the Royal Society of A^ictoria for 1 860, under its
present name. Rattray incomprehensibly calls it " Actinocyclus
Barklyi (Ehr.) Grun.," though he knew that it was named by
Coates, and not by either of the authors cited. He quotes a
reference to it in the Q. J. M. S. for 1861 (wrongly quoted as
"Plate CXXXVIII." instead of "Page 138 "), but does not refer
to Coates' original description. It is distributed by Moller under
the name A. dubius Grunow. It is one of the largest of the
genus (perhaps the largest), specimens in my slides attaining a
diameter of 0*24 mm., or more than double the maximum size
assigned to it by Rattray.

In normal valves the fasciculi are arranged much as in A.
Ralfsii, but great variety exists in the denseness or otherwise of
the granules, which, as in A. Ehrenbergii, also vary greatly in
sharpness. But it is in individual departures from the normal
arrangement that the tendency to variation exhibits itself in
such an extraordinary degree. In many cases the markings are
interrupted at a uniform distance from the centre, so as to form
a ring, and several such concentric rings may exist on one valve,

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 35

dividing it into zones. Sometimes the markings are denser on
one of these zones than elsewhere. Very often the zones form
hyaline bands on which the granules are wanting, and the
structure may be further complicated by the addition of radial
hyaline bands, e.g. two hyaline zones may be joined by a number
of equidistant radial hyaline areas so that the space between
them is divided into a circular series of sub-rectangular com-
partments ; or a broad circular zone may be filled with hyaline
patches of all sorts of irregular shapes. The radial series of
granules may be all curved in a spiral fashion (a variation
which also occurs in C. Ehrenbergii), and I have specimens in
which the central portion, as far as the first circular interruption,
has the moniliform series all contorted in the most extraordinary
manner. As in A. rex, etc., the subulate areas may be either
darker or lighter than the rest of the valve. There may be a
small central area, or the whole centre of the valve may be
sparsely and irregularly marked.

I find that in some slides concave and convex valves are mixed
about equally, leading to the conclusion that the two forms
represent opposite valves, as in A. rex, but in other gatherings
I find many concave valves to every convex one. Rattray de-
scribes the valves as flat in the centre and otherwise convex, but in
numerous cases the convexity (or concavity) is uniform throughout.
Asteromphahis. In this genus the lines which radiate from
about the head of the centro-lateral area to the apices of the
areolate compartments have been assigned too much value in
classification. Whether they originate from a single point, or
whether they bifurcate, is absolutely immaterial, and the presence
of geniculate bends in their course is, in some species at least,
equally unimportant. A. Hookeri, which is not rare in one of the
"Challenger" Antarctic soundings, illustrates this. The forms
with six, seven, eight and nine rays, which represent four of
Ehrenberg's "species," also a ten-rayed form, occur in slides
which I have prepared from this material, and 1 find the
geniculations of the radial lines very marked in some valves,
while others show no trace of them ; others again exhibit a mixed
condition. A good deal seems to depend on the size of the valve,
the geniculate lines being most common in the smaller ones.

Certain species are subject to variation in the outline.
A. Cleveanus, as figured by Schmidt, has a rather narrow ovate

36 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

form, but in mud from Manila it has a broader outline, and
I found one valve perfectly circular.

Actinoptychus. This genus is distinguished by its valves being
divided into six or more radial cuneate compartments, which are
alternately raised and depressed, the markings also differing (in
normal valves) on the elevated and depressed areas. On what
we may call, for want of a better term, the primary areas
{Hauptfelder of Schmidt), the coarse markings are usually more
robust, and often of different form, from those on the secondary
areas (Nebenf elder of Schmidt) ; further, the primary areas
usually bear a tooth or process near the margin, with, in some
species, a radial line connecting it with the umbilicus ; while the
secondary areas sometimes terminate in a submarginal hyaline
band, which is not found in the primaries. The fine striation
also is commonly different on the two sets of compartments.
The striation is generally fairly uniform within the limits of
a species, but the secondary markings, consisting of hexagonal
or irregular reticulation, or systems of branching veins, is most
variable in its distinctness, and is often wanting. When this
occurs it is generally assumed to be the result of the detachment
of the separate layer of the valve which is thus marked, but in
view of the fact that different valves exhibit every possible
degree of obsolescence of these markings, I have no doubt that
in many cases they have not been developed.

Among the characteristics to which too much importance has
been attached in classification are the number of areas, the
substitution of primary for secondary areas (so that all the areas
are alike), the presence or absence of the secondary markings,
also of the lines connecting the umbilicus with the processes, and
the presence of small variations in the striation. The adoption
of these purely artificial distinctions has led not only to the
undue multiplication of specific names, but, what is worse, to the
lumping together of forms which are by no means closely related.
In several species there are six areas, a number which is
rarely, if ever, departed from. Such are the forms composing
the group of which A. boliviensis is typical. In the majority of
species there is no constant number; for example the beautiful
A. Heliopelta, valves of which usually have six, eight, ten, or
twelve areas (constituting Ehrenberg's four species of Heliopelta),
while more rarely there are fourteen or sixteen. A. undulatus,

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 37

the most widely distributed species, is found in most localities with
six areas only, yet in some Calif ornian deposits it occurs freely
with up to eighteen areas, possibly more.

A. undulatus is a species which well illustrates the tendency of

the genus to vary in several directions, but the variations are

so numerous and so closely linked, and their relationships so

obvious, that they have not been made the basis of so many

pseudo-species as might have been expected. I have noted about

twenty-five forms sufficiently distinct to admit of their being

separated for convenience of cataloguing, but few of them are so

characteristic as to constitute definite varieties. In forms of

average size, which may be considered fairly typical, the secondary

markings are commonly about four in O'Ol mm., while in the

var. microsticta of Grunow, there may be about seven, and in

large forms like forma maxima Schmidt, there are only one and

a half to two. The reticulation may be either hexagonal or

irregular, robust or faint, and sometimes entirely wanting. The

sub-marginal processes are said to be sometimes absent ; in fact,

both W. Smith and Yan Heurck appear to regard this condition as

typical, but I have not seen specimens without some trace of them.

(The obsolete genus Omphalopelta comprised the valves with

processes.) The processes may be very small, appearing merely

as a slight thickening of the border, or may be placed a little

farther in, presenting a somewhat irregular keyhole-shaped

aspect. In many forms the secondary areas have on their

margin a small hyaline patch in the corresponding position to

that occupied by the processes in the primaries. On both sets

of areas the outermost portion, immediately adjoining the margin

proper, usually bears radial lines, being continuations of the

boundaries of the last row of secondary markings, which, like the

secondary markings generally, are most robust on the primary

areas. The rim may be smooth, or may have few or many

minute apiculi scattered over it. The puncta which compose the

striae of the primary areas are arranged in quincunx, so that the

striation is the same as in Pleurosigma angulatum, but those of

the secondary areas form two sets of diagonal striae cutting each

other at right angles, as in P. formosum. Schmidt describes as

A. biformis valves in which these two sets of striae meet at

rather less than a right angle, so that a third set is visible,

closer than the other two, and crossing the area transversely.

38 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

Some valves which I have seen with this character were in all
other respects similar to normal valves of A. undulatus, among
which they occurred, and I see nothing to justify their separation,
the slight divergence from the rectangular arrangement of the
striae being no more than is often found in P. formosum. Some-
times the striae meet at more than a right angle, so that the
third set is radial instead of tangential. If Schmidt's species
were accepted, this should make another species ! The striae are
sometimes nearly or quite obliterated on small patches at the
outer angles of the secondary areas, and occasionally along the
margins ; in some forms again they are wanting or represented
only by a few scattered puncta on a great part of those areas.
The umbilicus varies greatly in size, and may be either hexagonal
or may have three concave sides. Much variation exists in the
extent to which the areas are inflated, or, in other- words, in the
depth of the undulations.

A consideration of the variations of this diatom will show how
many features there are which, met with in isolated forms, may
lead to the undue multiplication of species.

In several species, perhaps in the genus generally, there is
a tendency to produce valves in which the secondary areas or
" Nebenfelder " are replaced by primary ones or " Hauptfelder,"
so that all the areas become alike, except in their elevated or
depressed condition. Van Heurck has figured such a form of
A. undulatus the forma sexapjiendicidata, which he says may
co-exist in the same frustule with the normal form. He refers
only to the presence of a process on every area, and does not
mention that the areas are otherwise modified, which, however,
I have always found to be the case. Other varieties of
A. undulatus exhibit the same tendency ; thus the large forma
maxima found in the Nottingham deposit is accompanied by its
"forma sexappendiculata" as also is an equally large variety
which only differs from it in the strongly apiculate margin. In
all these cases the compartments all correspond exactly with the
normal primary areas, both in the striation and the coarser
secondary markings. There may possibly be varieties with this
as the usual condition, as I have found one or two such forms
sparsely distributed in material where I noticed no typical valves
to which they might correspond.

In A. Heliopelta also valves are formed in which all the areas
are alike, instead of alternately primary and secondary.

It is to be noted that in all species where this phenomenon

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 39

occurs it is always the primary area, with its process, which is
duplicated ; we never see valves with all the areas alike and
having the distinctive markings of the secondary ones.

Notwithstanding that it has been recognised that in A. undu-
latus the variation in question has no specific importance, being
found, in fact, in frustules otherwise normal, a parallel variation
in other cases has been made a ground for the foundation of new
species, even by observers as recent as Grunow and Schmidt.
Such instances are A. Janischii Grun., which, as I shall
demonstrate, is only a state of A. splendens, and A. Molleri
Grun., which is a form of A. adriaticus Grun. Van Heurck says
of A. Janischii that it " se distingue de toutes les autres especes
du genre en ce que la valve a toute juste moitie autant
d'ondulations que de divisions, de facon qu'une elevation n'est
suivie d'une autre elevation que pres da deuxieme appendice
suivant. Une espece analogue mais plus petite est V A. Jfolleri
d'Adelaide, qui se distingue en outre par sa structure plus
delicate et l'absence d'une ligne mediane." This is simply
equivalent to saying that each area, instead of each alternate
area, bears a process, and it is surprising that the writer did not
observe that the character referred to as so exceptional was no
other than he has figured in the same plate in the forma
sexappendicidata of A. undulatus.

A. glabratus Grunow and A. Janischii Grunow are, in part at
least, forms of A. splendens, but there is a difference in the
relationship which they bear to that species, A. glabratus
simply consisting of valves wanting the secondary markings,
while A. Janischii is an internal disc. A. splendens commonly
has a distinct secondary layer showing more or less branching
venation, with the typical distinction between primary and
secondary areas, but a gathering usually includes a propor-
tion of valves in which the secondary layer is wanting ; and
although there is every possible gradation, the smooth valves
have been described as a doubtful species, under the name of
A . glabratus. Also accompanying them are valves in which all
the compartments bear processes, and to these the name
A. Janischii has been given, Janisch having figured one of
them (as Halionyx vicenarius) in his paper on diatoms from
guano. Tn Peru guano A. splendens is one of the commonest
species, and the typical valves, with their glabratus-iovms and
Janischii-iovms, are readily obtained. In a Cuxhaven gathering
I also find all three forms together. And in a slide of Thum's,

40 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

which contains a very robust variety, all three forms are
similarly associated. In the valves described as A. Janischii
the marginal sculpture differs somewhat from that proper to
A. splendens, but this is a necessary concomitant of the substi-
tution of primary for secondary areas. In A. splendens, as in
several other species, the secondary areas terminate in a sub-
marginal hyaline band, which encroaches slightly on the primary
areas at each side of it. When, however, all the areas have the
same structure, this band is wanting, all except the small portion
which properly belongs to the primary areas, so that a small
rounded hyaline patch opposite the edges of the compartments is
all that remains.

The relationship between these forms has always appeared to
me obvious, as it evidently did to Ralfs, who describes A. splendens
as having a tooth on each compartment, or sometimes only on
alternate compartments. In order to obtain actual proof of this,
however, it occurred to me to examine some Peru guano
cleanings which had furnished numerous slides, but in which the
complete frustules of A, splendens, where they occurred, had been
left. I picked out ten of these and mounted them in balsam,
with the result that I found that three out of the ten contained
valves of the so-called A. Janischii, each being included in a
frustule between two of the normal valves. In all cases where I
have examined whole frustules of A. splendens I have found that
the two valves were either alike in the number of areas, or one
valve had a pair more than the other. Thus, if one valve had
sixteen areas it could be predicated that the other would have
fourteen, sixteen or eighteen. Where an internal disc was
found (A . Janischii) it had the same number of areas as one of
the outer valves. In the slide referred to one frustule had the
outer valves with fourteen and sixteen areas respectively, and the
internal disc with sixteen ; another had the outer valves with
sixteen and eighteen, and the inner with eighteen ; and the third
had twenty throughout. The areas of the inner disc have the
processes rather smaller than those of the outer valves, and
nearer the margin. Though the inner disc is usually smooth,
like the so-called A. glabratus, this is not invariably the case. I
have a specimen covered with reticulations as distinct as in the
typical valves.

In Van Heurck's opinion several genera, as well as species,
have been founded on mere internal valves of various species of
Actinoptychus (as also of Asterolampra). Such are Debya and

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 41

Gyroptychus, Debya being an internal disc of A. undidatus, very
unlike the outer valves, and found by Van Heurck inside the
normal frustules. The A. jjellucidus Grunow, figured in Van
Heurck's synopsis, PI. 123, fig. 1, is, as will be obvious to any one
who compares it with the figure of A. Heliopelta in the same
plate, merely a valve of the latter with the border wanting and
the secondary reticulation undeveloped. In a genus-slide by
Thum I have several such valves, but for the most part they
retain a little more of the border, showing the origin of the
spines, and some of them also have the secondary markings more
or less distinctly indicated.

In many marine gatherings from Port Phillip a form of
A. adriaticus is found in great profusion, of which a specimen is
figured in Schmidt's Atlas, PI. 153, fig. 14. It varies greatly in
the distinctness or otherwise of the secondary markings, and
especially in the presence or absence or fragmentary condition of
the narrow radial lines which in the typical A. adriaticus, as in
A . splendens, run outward from the umbilicus, or near it, to the
processes. In most slides a few specimens may be found with all
the areas alike, and a process on each, and it is this form which
has received the name of A. Molleri Grunow.

Normally the areas are arched at the ends, as shown in Van
Heurck's figures, the secondary ones being shorter than the
primary, with a wide hyaline band outside them, but as in the
form called A. Molleri they are all primary areas, and conse-
quently of the same length, the hyaline band is reduced to a small
triangular area at the junction of every two compartments with
the margin. All the variations of marking which occur in the
normal valves are found equally in this form, and their specific
identity is obvious. In reality, this so-called A. Molleri is the
true A. adriaticus described by Grunow, his original figure
showing a valve with processes on all the areas, and exactly the
same marginal sculpture as described above. It is true A. Molleri
is supposed to be without the radial lines to the processes, but
Grunow recognised in his original description of A. adriaticus
that these lines might be present or not, in which he was
certainly correct.

These radial lines, however (sometimes called pseudo-raphes),
appear to be considered by Van Heurck as distinguishing
A. adriaticus from A. vulgaris, though he admits a possible
exception in A. adriaticus var. pumila. In the common
Australian form, however, it is obvious that the presence of

42 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

these lines has no specific or varietal significance whatever.
Almost every gathering shows valves both with and without
them, and innumerable specimens exhibit an intermediate con-
dition, i.e. where the lines are more or less broken, or where they
are present on some of the primary areas of a valve and not on
others. They are scarcely ever complete, but generally stop
short of the umbilicus, as in the var. balearica. Valves without
them are otherwise identical with those possessing them, having
exactly the same range of variation in other respects, and this
applies equally to the so-called A. JIdlleri.

While reliance on such characters as the foregoing leads to the
improper separation of allied forms on the one hand, it tends in
other cases to the opposite error. Thus several varieties of
A. glabratus have been described, and while some are, as before-
mentioned, only smooth valves of A. splendeiis, there are others
which, so far as I know, cannot be identified with any special
form of that species, and which may probably be themselves
entitled to specific rank. A. vulgaris also, as generally under-
stood, includes forms which have really no close relationship.
One such form is nothing but A. undulatus^ as it is found in
Redondo Beach and other deposits, with mostly fourteen areas.
The deposit mentioned contains numerous valves of the ordinary
form, with six areas, a few with eight, ten and twelve, a good
many with fourteen and a few with sixteen and eighteen. The
structure of these is absolutely identical with that of the six-
rayed forms, and it is as absurd to separate them as it would be
to separate forms of A. Heliojjelta with six areas from those with
more. Other forms commonly ranked under A. vulgaris are
simply valves of A. adriaticus with the pseudo-raphes wanting,
as already described, while others seem to be similar, but with
deeper and more abrupt undulations. The undulations in
A. adriaticus are very shallow, so much so that Grunow origin-
ally described it as flat ; but in view of the considerable variation
in this respect found in the valves of A. undulatus and other
species, the character would seem to be of doubtful importance.

Probably the nearest approach to a really flat condition is
found in the three-sided A. mari/landicus, in which the six areas
show a very slight difference of level near the centre only, else-
where blending with each other imperceptibly. This species has
a more or less distinctly three-sided umbilicus, and appears to be
identical with the Symbolophora trinitatis of Ehrenberg. Ralfs
has argued against this view on the ground that >S'. trinitatis is

W. M. BALE ON SOME OF THE DISCOID DIATOMS. 43

circular, while A. marylandicus is three-sided, but in Atlantic
City slides valves of the latter species are found in which the
divergence from the perfectly circular form is scarcely perceptible,
so the objection falls to the ground.

It is sometimes stated as a character of the genus that the
depressions of one valve correspond to the elevations of the other,
so that the frustule is radially undulated as a whole. That this
is not alwavs the case is evident from the fact that the two valves
have often a different number of areas. But I find on comparing
a number of species that there is considerable variation in regard
to the undulations. First we have forms in which the undula-
tions extend to and include the rim itself, so that one valve
necessarily fits into the other. A striking example is A. trilingu-
latics, in which the whole valve is so strongly undulated that only
three points of the margin can be seen at any one focus. Then
we have such species as A. undulatus and A. Heliojwlta, in which
the undulations do not extend outward to the margin. Apart
from the border itself, the sub-marginal zone is about on a level
throughout, but the one set of areas is inflated as much above
that level as the other is below it. The border itself slopes down
rather steeply, but the depressed areas often reach as low a level
as the extreme margin. Still, the width of the hoop ensures that
such valves may be placed with the depressions opposite each
other without coming into contact. Lastly, in A. splendens the
depressions do not reach as low as the margin, while the eleva-
tions rise considerably above it ; even with a narrow hoop,
therefore, there is no question of the depressed areas of opposite
valves clashing.

According to the definitions of Ralfs and Yan Heurck, a
character of the genus is the division of the valve into equal
cuneate segments, which would exclude from it the A. hispidus
Grunow (Van Heurck, Synopsis, PI. 123, fig. 2), a species which
is described as having narrow elevated compartments alternating
with wide depressed ones. I believe, however, that the so-called
elevated compartments of A. hisjndus are not compartments at
all in the same sense as those of Actinoptychiis ; neither are they
elevations, but only appear so owing to having depressions on
each side of them. The valve is a shallow cone, by far the
greater part of which is occupied by about eight or nine broad
radial cuneate areas, all of which are depressions. The linear
rays or ridges are simply parts of the surface not included in the
depressions, but dividing them. These rays slope down evenly

44 W. M. BALE ON SOME OF THE DISCOID DIATOMS.

from the umbilicus and join the sub-marginal zone without any
interruption of the structure, which indeed is similar all over the
valve, except the narrow hyaline border. The valve is very thin,
covered with very delicate striae, crossing each other obliquely,
and most easily seen on the narrow rays. The secondary
markings consist of a fine, delicate, irregular reticulation, at the
angles of which are dark points or apiculi, which are larger and
darker on the narrow rays and sometimes round the inner border.
On each of the linear rays, near the border, is a minute process.
In Grunow's figure both the cuneate areas and the dividing rays
are abruptly truncate at the border, but my specimens do not
agree with this, as the narrow rays widen out in a regular curve
towards the border zone, with which they are continuous, the
cuneate areas having of course their outer corners rounded off
correspondingly, while they do not quite reach the border. Owing
to the thinness of the valve, however, and the depressions being
by no means abrupt at the outer ends, this character might often
pass unnoticed, unless the valve happens to be lying obliquely,
when it becomes more conspicuous. Possibly my specimens, which
were found in recent gatherings from Port Phillip, may differ
specifically from Grunow's guano specimens, but the late
Mr. Comber considered them the same.

I think the characters by which this species is distinguished
from all others of the genus are such as to entitle it to at least
the rank of a sub-genus, for which I would suggest the name
Radiodiscus. It is possible, however, that it may be brought
under the genus Actinodictyon Pantocsek, but I am uncertain
of the affinities of that genus, of which I have seen no specimens.

I have a single valve, apparently belonging to A. hispidus,
which differs in several respects from the usual form. Its
depressions are extremely slight, there are no secondary markings
and no apiculi, and the cuneate areas terminate in a hyaline
band, as in A. splendens, etc.; it also has exceedingly narrow
lines (pseudo-raphes) on the narrow areas ; the border is wanting.
It may be a varietal form, or possibly an internal disc, but its
pseudo-raphes and hyaline bands seem to indicate a closer affinity
with such forms as A. adriaticus than would be inferred from the
typical form.

Journ. Quckett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913.

45

SOME NOTES ON BRITISH FRESHWATER RHAB-
DOCOELIDA A GROUP OF TURBELLARIA.

By Henry Whitehead, B.Sc.

(Read January 28th, 1913.)

Plate 4.

The members of the group Rhabdocoelida are very similar as
regards appearance, shape and movements to the Infusoria,
though they are generally much larger and their complicated
internal structure enables them to be distinguished at a glance.
The Rhabdocoelida form a branch of the group Turbellaria,
to which the larger Planarians found in fresh water also belong.
The Turbellaria, in turn, together with the Liver-flukes and
Tape-worms, are included in the phylum Platyhelminthia
or Flat-worms.

The British marine Turbellaria have been monographed by
Prof. Gamble (12), and our President has taken an active part in
the study of the land Planarians of Australasia. The freshwater
Turbellaria have apparently received but little attention in this
country, though Prof. Gamble publishes a list of British species
in the Cambridge Natural History (14).

As the larger freshwater Planaria (Tricladida) cannot be
regarded as microscopic objects, and are therefore of no special
interest to the Club, the writer proposes, in this paper, to deal
only with the group Rhabdocoelida.

Yon Graff has written two monographs on this group, and has
devoted much time to valuable work on anatomical features ;
and it is chiefly from these sources that the information con-
tained in this paper has been derived.

The writer does not propose dealing in detail with the
anatomy, but rather to deal with the Rhabdocoels from a general
point of view, emphasising matters of particular interest to the
field naturalist.

The freshwater Rhabdocoels vary in size from 1/2 5th to half

46 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA

an inch in length. They are generally found in ponds, lakes
and ditches, and less frequently in running water. Like many
other microscopic inhabitants of ponds, they appear in great
abundance at certain seasons of the year and then suddenly
disappear.

The body is more or less transparent, slightly flattened, and is
provided with cilia. The Turbellaria are remarkable for peculiar
secretions given off from the epidermis. These secretions are of
two distinct kinds one a mucous fluid, and the other con-
sisting of very small solid bodies, or rhabdites, which, on coming
in contact with the water, produce mucus. Several forms of
rhabdites have been described (spindle-shaped, rod-shaped, egg-
shaped and spherical). They are formed in special glandular
cells which lie beneath the epidermis, and the rhabdites pass to
the surface by means of minute ducts.

Another interesting feature is the presence, in certain species,
of nematocysts similar to those found in Hydra.*

The Rhabdocoels are provided with a mouth, a pharynx and
an unbranched, sac-like gut. The position of the mouth varies
and affords a valuable generic character. It may lie at the
extreme anterior or in a median position anywhere along the
ventral surface as far down as two-thirds of the body length.

The excretory system consists of renal organs which are, in
some cases, somewhat complicated in structure.

The nervous system is simply, and comprises a two-lobed brain
and a pair of nerves running along the body close to the ventral
surface. In some species the pigmented eyes are clearly defined,
in others the eye pigment is scattered, and in some cases eyes
are absent.

Some of the freshwater Rhabdocoels have at their anterior
end pit-like depressions which contain cilia (PI. 4, fig. 3, cp).
The ciliated pits rest upon a group of ganglion cells which are
connected with the brain. Similar structures are found in
Nemertine worms, and some zoologists consider that this
suggests affinity between the groups. Another interesting organ
is the statocyst, which is present in some species. This consists
of a cavity containing fluid, in which is suspended a highly

* Mr. Scourfield has recently called my attention to a paper by C. H.
Martin (20) on this subject. The author shows conclusively that the
nematocysts are derived from the prey upon which the Turbellarian feeds.

A GROUP OF TURBELLARIA. 47

refractive particle of calcium carbonate the otolith (or statolith).
The statocysts serve as organs of equilibration.

Reproduction is, in most cases, sexual. The animals are
hermaphrodite, but the male organs ripen first. The sexual
organs are very complicated, and the details of their structure
are of great value in classification. On this account it is often
impossible to determine the species of immature individuals, and
sometimes it is necessary to have specimens in both the male and
the female stages before identification can be certain. Fresh-
water Turbellaria undergo no metamorphosis, and newly hatched
individuals are similar to their parents in general appearance.

Asexual reproduction occurs only in the section Hysterophora.
A chain of individuals is formed by the development of mouths,
eyes, etc., at intervals along the body. Constriction of the body
and gut then follow, and fresh individuals are produced by
fission. The process is illustrated in PI. 4, fig. 3. Some species
which reproduce asexually throughout the year develop sexual
organs in the autumn. These produce eggs which lie dormant
through the winter.

Considerable interest has recently been aroused in certain
green or yellow cells which are found in the bodies of some
species of Turbellaria. The green cells contain chlorophyll and
are able to decompose carbon dioxide in the presence of sunlight.
Two marine species, Convoluta roscoffiensis and G. jmradoxa,
found on the coast of Brittany, have been the subjects of detailed
study, and the results have been summarised by Prof. Keeble in
a little book entitled Plant- Animals. The genus Convoluta
belongs to a group of Turbellaria, the members of which have
not, up to the present, been found in fresh water. The green cells
or zoochlorellae, as they are termed, are now regarded as algae
similar to Chlamydomonas. In the case of Convoluta it is
certain that the presence of zoochlorellae is of benefit to the
Turbellarian, and that the relationship is a true symbiosis.

Von Graff (17) mentions twenty-five species of freshwater
Rhabdocoels in which green cells have been found. The fresh-
water species containing zoochlorellae have not been well
studied, and some zoologists doubt whether there is mutual
benefit in the association. This aspect of the subject will,
however, be dealt with later.

The Rhabdocoelida live under various conditions, but generally

48 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA

prefer still or gently flowing water to rapid streams. One
species, Prorhynchus stag7ialis, is sometimes found on moist earth.
Many of the aquatic forms are free swimmers, and may be
captured in the net in the same way as rotifers and water-fleas ;
others live in mud. In the latter case it is best to pour a little
of the mud into a glass tank containing clear water, and to
remove any Rhabdocoels by means of a pipette. They should
be examined in a live box, and it will be found that a slight
pressure is necessary to ensure making out their internal
structure. They are very difficult to prepare in a satisfactory
manner as permanent objects, and the writer has made numer-
ous experiments with a view to narcotising them, but with
little success. Eucaine, chloroform, ether and alcohol are of no
use. The difficulty seems to lie in the fact that the rhabdites
are discharged as soon as the animal is irritated, and these, of
course, produce quantities of mucus. Moreover, the epidermal
cells get destroyed during the process. The only satisfactory
method of killing seems to be by means of some hardening re-
agent, like corrosive sublimate solution, which takes effect before
the mucus and rhabdites can be discharged. The following well-
known method is the best. The specimen is placed in a watch-
glass with a little water, the bulk of which is withdrawn by a
pipette. A drop of Lang's Fluid is then delivered from a pipette
on the side of the watch-glass and is allowed to run over the
animal. Death is almost instantaneous, and but little shrinkage
takes place. Even with this method the writer has not yet
succeeded in killing species of Mesostoma without disruption.
After remaining in Lang's Fluid from ten to fifteen minutes,
the specimens are removed to 45-per-cent. spirit. They are
afterwards passed through alcohol of increasing strength, stained
with borax-carmine and mounted in Canada balsam in the usual
way.

Some of the Rhabdocoels appear to be entirely vegetarian in
diet, and consume desmids, diatoms and unicellular algae. In
fact, care is sometimes necessary to distinguish the food from
the zoochlorellae. The latter, however, never occur in the gut.
The majority of species take animal food, which consists of water-
fleas, small worms, etc.

We may now consider a few typical species which have been
taken by the writer in the neighbourhood of London.

A GROUP OF TURBELLARIA. 49

Catenula lemnae (Ant. Dug.).

Occurs in ponds and lakes, and often appears suddenly in
considerable numbers in collections of rain-water during the
spring and summer, and disappears as rapidly as it comes.
It is white and thread-like in appearance, consisting of a chain
of 2 4 individuals (rarely more) and attaining a length of
5 mm. The body possesses a well-defined head lobe, which is
marked off by a slight constriction and a ring of comparatively
long cilia ; a statocyst is present. The usual mode of repro-
duction is by fission, but sexual organs are developed when the
pond or ditch begins to dry up.

Microstomum lineare (Mull.) (PI. 4, fig. 3).

This species is very similar to the foregoing, but the colour is
yellowish or greyish brown. It is usually found in the form of
a chain of zooids of which there may be as many as 18. The
colony attains a length of 8 mm. Each zooid develops a pair of
red eyes, behind which may be seen the ciliated pits. The skin
is thickly clad with cilia. No rhabdites are present, but
nematocysts, similar in form to those of Hydra, are present (20).
The figure shows the manner in which new individuals arise, and
various stages in the formation of mouths may be seen. The gut
is common to all the zooids in the chain, until fission takes place.
The writer has seen desmicls which had been swallowed for food
pass along the common gut from one zooid to another. Sexual
organs are sometimes produced, and the ripe eggs are oval in
shape and orange or dark red in colour.

This species is fairly common in stagnant or slowly moving
water. It has been found in thermal springs at a temperature
of 130 F. and also in brackish water. It moves slowly on a
surface, but is a graceful and swift swimmer.

Dalyellia viridis (G. Shaw) (PI. 4, figs. 1 and 2).

Examples of this species attain a length of 5 mm., and are
generally spinach-green in colour. The colour is due to the
presence of algal cells Which lie beneath the epidermis. The
body is truncated in front, widens towards the middle and
then tapers towards the tail. There are two bean-shaped eyes.
There is a very distinct pharynx and the gut is sac-like.

Journ. Q. M. C, Series II. No. 72. 4

50 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA

Specimens of this interesting Rhabdocoel were taken in one of
the ponds in Richmond Park, on the occasion of the Club's visit
on April 13th, 1912. The following week the writer took
specimens from a pond near Chigwell Row, Essex.

It was noticed that the animals had a number of eggs (in one
instance 49 were counted) in the spongy body tissue, and
individuals in this condition avoided the light. As far as could
be ascertained, no eggs were deposited by the living animals, but,
on death, the eggs were liberated on the decomposition of the
body of the parent. So far none of these eggs have hatched.

Prof. Sekera (16) of Tabor, Bohemia, succeeded in keeping

specimens alive for some time, and the following notes are taken

from the account of his observations. Young specimens were

taken in ponds in March, when ice was still floating on the

water. The animals were colourless, but as soon as they

approached maturity, and the sexual pore developed, it was

noticed that a few algal cells (zoochlorellae) had entered the

body cavity by this means. Streaks of green granules then

began to spread from this region and extend beneath the cuticle

over the whole body, until finally the animal became quite

green. (T would remark, in parenthesis, that mature specimens

show distinct lines or bands devoid of zoochlorellae.) Solid

food in the form of diatoms, rotifers, etc., was ingested during

this period. While rapid division of the algal cells was taking

place, they formed spherical or ellipsoid clusters, each group

being surrounded by a colourless membrane. The membrane

finally disintegrated and the algal cells were dispersed in narrow

irregular lines or bands. The mature zoochlorellae showed no

signs of an enveloping membrane. The animals exhibited at

this period a distinct tendency to crawl towards light (phototactic),

but sank to the bottom of the vessel at night. During the third

week eggs were formed in the body cavity. The worms at this

stage began to avoid the light and spent the whole day at the

bottom of the vessel or under vegetation. During the first week

in May the animals died off rapidly, and with the decomposition

of the body the eggs were liberated. The algal cells were set

free and continued to live, and developed an investing membrane,

then passed into a resting stage, probably awaiting an opportunity

of invading the next generation of Dalyellia.

Prof. Sekera thinks that the alga is of little or no value to the

A GROUP OF TURBELLAEIA. 51

animal in the way of providing food, his reasons being that
closely allied species, living under similar conditions, do not con-
tain algae, and that solid food is ingested after the algal cells are
fully developed. The writer hopes to investigate this question
more fully, for Sekera's argument does not seem to be quite
conclusive.

Sir J. G. Dalyell (1) wrote an account of this interesting
species in 1814, and states that it sometimes occurs in large
numbers, and then suddenly disappears. He found his specimens
chiefly in the spring, but some were found in the autumn.

Mesostoma Spp. (PL 4, fig. 4).

Some of the species of Mesostoma produce two kinds of eggs
thin-shelled and thick-shelled. The thick-shelled eggs, which
contain a large quantity of yolk, are produced in the late summer
and lie dormant during the winter. The young hatched from
these so-called " winter " eggs, when less than half the size of the
parent commence to produce thin-shelled eggs with but little
yolk. It is probable that these eggs are unfertilised ; they are
produced in great numbers and begin to hatch in April and May.
The young hatched from these eggs attain full development
and produce thick-shelled " winter " eggs, which have been
fertilised (14).

There is some difference of opinion amongst observers as to the
precise nature of the life-cycle in this genus. See von Graff (17).
They vary in size from 3 to 15 mm. in length according to
the species and condition. They live in clear, still or slowly
flowing water and swim or creep over water-plants. Their food
consists of entomostraca, small worms, etc., which are sometimes
caught by means of slime threads.

Bothromesostoma personatum (Schm.).

Specimens of this species attain a length of about 7 mm. and
are easily identified by two white patches which look like large
eyes on each side of the "head." The rest of the body is either
grey or black. The writer has taken specimens on the leaves of
water-lilies and creeping on the surface film, at Staines and at
the East London Waterworks. The genus Bothromesostoma is
closely allied to Mesostoma, and like the latter produces both
summer and winter eggs.

52 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA

Gyratrix hermaphroditus Ehrbg. (PI. 4, fig. 5).

This species appears to be widely distributed. It is about
2 mm. in length, is almost transparent and is a rapid and
graceful swimmer. It can easily be recognised by the com-
paratively long stiletto at the posterior extremity. This weapon,
although connected with the male copulatory apparatus, is
furnished with a gland which probably secretes a poison of some
kind and is used by the animal when attacking its prey. It has
a well-marked proboscis, behind which are two eyes. The mouth
and pharynx are situated near the middle. As a general rule,
only one egg-capsule is present, and this produces one or two
embryos.

The field is almost unworked as regards this country. Von
Graff records 110 species of Ehabdocoelida from Germany. As far
as the writer can ascertain, only 30 species have been recorded
from the British Isles. It is hoped that this short account
mav arouse the interest of some of the members of the Quekett
Microscopical Club in these interesting animals.

List of British Species.

In the following list the descriptions of the species will, unless
otherwise stated, be found in Die Silsswasserfauna Deutschlands,
Heft. 19. The initials H. W. after the localities denote that the
species has been found by the author at those places :

Sub-order RHABDOCOELA.

Section Hysterophora.

Fam. CATENULIDAE.

Catemila lemnae Ant. Dug.
Near Cork (14).

Stenostomum leucops (Ant. Dug.).

Common (14) ; Clare Is. (24) ; Staines (H. W.).

S. unicolor 0. Schm.
Clare Is. (24).

Journ. Q.M.C.

Ser. 2, Vol. XII., PI. 4,

rw

H W del.

Rhabdocoelida.

A GROUP OF TURBELLARIA. 53

Fam. microstomidae.

Microstomum lineare (Miill).

Fresh water (14) : Chigwell : Higham's Park, (H. W.) ;
" In all Scottish lochs " (19) ; near Dublin (21).

Macrostomum appendiculatum (0. Fabr.) (= hystrix,
Oe).
Stagnant water (14) ; Clare Is. (salt water) (24).

Fam. PRORHYNCHIDAE.

Prorhynehus stagnalis M. Schultze.

In Devonshire rivers (14) ; L. Lomond (19) ; Fenton
Tower, E. Scotland (9).

P. curvistylus M. Braun.
Near L. Lomond (19).

Section Lecithophora.

Fam. DALYELLIIDAE.

Dalyellia diadema Hofsten (18).

Chigwell Row (H. W.). This species appears to have been
recorded only once before, viz. in the Bernese Alps.

D. viridis (G. Shaw) (= heUuo Miill).

Generally distributed (14) ; Richmond Park, Chigwell
Row (H. W.) ; Edinburgh (9).

D. armigera (O. Schm.).
Millport (14).

D. Schmidtii (L. Graff).
Millport (14).

D. millportianus (L. Graff) (9).
Millport (9).

Jensenia agilis Fuhrm (= serotina, Dorner).
Richmond Park, Epping Forest (H. W.).

J. truncata (Abildg.).

Abundant in fresh water (14), L. Lomond (19).

Phaenocora (= Derostomum) punctatum Orst.
Theydon Bois (H. W.) ; Edinburgh (9).

Opistomum Schultzeanum Dies.
L. Lomond (19).

54 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA

Fam. typhloplanidae.

Rhynchomesostoma rostratum (Miill).

Widely distributed (14) ; Millport, Edinburgh (9).

Typhloplana viridata (Abildg.) ( = Mesostoma viridatum
M. Sch.).
Manchester (14) : Clare Is. (24).

Mesostoma productum (0. Schm.).
Cambridge (14).

M. lingua (Abbild.).
Cambridge (14).

M. Ehrenbergii (Focke).

Cambridge (14).

M. tetragonum 0. F. M.

Cambridge (14).

M. Robertsonii L. Graff. (9).
Millport (9).

M. flavidum L. Graff. (9).
Millport (9).

Bothromesostoma personatum. (0. Schm.).

Preston (14) ; Staines, E. Lon. Waterworks (H. W.).

Fam. POLYCYSTIDIDAE.

Polycystis Goettei Bresslau.

Nr. Abergavenny, L. Lomond (19).

Fam. GYRATRICIDAE.

Gyratrix hermaphroditus Ehrbg.

Common in fresh water (14) ; Chigwell Row (H. W.) ;.
St. Andrews (salt water) (9) ; Clare Is. (salt
water) (24).

Sub-order ALLOEOCOELA.

Fam. OTOPLANIDAE.

Otomesostoma auditivum (Pless.) ( = Monotus morgiensis
et relictus Du Plessis).
Deep waters of Scottish lochs (19).

A GROUP OF TURBELLARIA. 55

Fam. BOTHRIOPLANIDAE.

Bothrioplana sp. ?
Manchester (14).

Euporobothria bohemica (Vejd.).
Tarbet, L. Lomond (19).

Bibliography.
Confined to the more important works or to papers quoted.

1. 1814. Dalyell, J. G. Observations on Planariae.

2. 1848. Schmidt, E. 0. Die Rhabdocoelen (Strudelwiirmer)

des Siissenwassers.

3. 1853. Dalyell, J. G. The Powers of the Creator, vol. ii.

4. 1865. Johnston, G. A Catalogue of the British Non-para-

sitical Worms in the British Museum.

5. 1867. Lankester, E. R. Planariae of our Ponds and

Streams. Pop. Sci. Rev., vi., pp. 388-400.

6. 1868. Houghton, W. Our Freshwater Planariae. In-

tellectual Observer, xii., pp. 445-449.

7. 1878. Jensen, O..S. Turbellaria ad litora Norvegiae.

8. 1879. Hallez, P. Contiibutions a l'histoire naturelle des

Turbellaries.

9. 1882. Graff, L. von. Monographie der Turbellarien. I.

Rhabdocoeliden.

10. 1885. Braun, M. Die Rhabdocoeliden Turbellarien Liv-

lands.

11. 1885. Graff, L. von. Article " Planarians " in Encyc. Brit.

Ninth Edition.

12. 1893. Gamble, F. W. Contributions to a knowledge of the

British Marine Turbellaria. Quart. Journ. Micro.
Science, vol. xxxiv., p. 433.

13. 1894. Fuhrmann. Der Turbellarien der Umgebung von

Basel. Revue Suisse de Zoologie.

14. 1901. Gamble, F. W. Flatworms and Mesozoa in Cam-

bridge Nat. Hist., vol. ii.

15. 1901. Benham, W. B. Lankester's Treatise on Zoology.

Pt. IV. Platyhelmia.

16. 1903. Sekera, E. Einige Beitrage zur Lebensweise von

Vortex helluo. Zool. Anz., xxvi., pp. 703-710.

56 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA.

17. 1904-8. Graff, L. vox. Das Thierreich, Turbellaria. I.

Acoela und Bhabdocoelida.

18. 1907. Hofsten, Nils von. Studien iiber Turbellarien aus

dem Berner Oberland. Zeitschr. f. wiss. Zoologie,
lxxxv., pp. 391-654.

19. 1908. Martin, C. H. Notes on some Turbellaria from the

Scottish Lochs. Proc. Roy. Soc. Edin., vol. xxviii.,
pp. 28-34.

20. 1908. Ibid. The Nematocysts of Turbellaria. Quart.

Journ. Micro. Sci., vol. lii., pp. 261-277.

21. 1908. Southern, R. Handbook to City of Dublin. Brit.

Assoc.

22. 1909. Graff, L. von. Die Siisswasserfauna Deutschlands.

Heft. 19.

23. 1911. Ibid. Acoela, Bhabdocoela und Alloeocoela des ostens

der vereinigten staaten von Amerika. Zeitschr.
wiss. Zoologie, xcix., pp. 1-108.

24. 1912. Southern, R. Clare Island Survey. Pt. 56. Platy-

helmia. Proc. Roy. Irish Acad., xxxi.

Description of Plate 4.

Pig. 1. Dalyellia viridis, entire, x 15.

2. Chitinous copulatory organ of D. viridis, X 150.

3. Microstomum lineare, entire, x 20.

4. Mesostoma sp., entire with thin-shelled eggs, x 20.

5. Gyratrix hermaphroditus, entire, X 45. b c, bursa copu-
latrix ; c, cocoon ; c p, ciliated pit ; e, egg ; g, gut ;
m, mouth ; o v, ovary ; p, poison-sac ; p h, pharynx ;
p r f proboscis ; s t, stiletto ; it t, uterus.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913.

57

THE ROTIFERA OF DEVILS LAKE, WITH DESCRIP-
TION OF A NEW BRACHIONUS.

By Charles F. Rousselet, F.R.M.S.

{Read January 2%th, 1913,)

Plates 5 and 6.

Devils Lake, the largest body of water in North Dakota, U.S.A.,
is approximately 30 miles long by 5| miles wide at its broadest
part, and of very irregular shape. It receives its water from
a territory which forms an inland drainage basin extending
northwards as far as the Turtle Mountains.

From the records it appears that the level of the lake has
fallen 14 feet since 1883 (when it stood at 1,439 feet above sea-
level) and 16 feet between 1830 and 1883, making a total
recession of 30 feet in eighty years with a corresponding shrink-
age of the area of the lake. At the time of its highest level the
lake had an overflow outlet at its eastern end into Stump Lake
lying further east, and it is probable that this high-water level
was reached many times in past centuries through periods of
scanty rainfall succeeded by periods of unusually abundant pre-
cipitation. In 1910 the level of the water stood at 1,425 feet
above sea-level, but fluctuates about 4 feet between very dry
and wet periods. The lake has had no outlet for a long period,
and as the result of evaporation the water has become brackish,
the salinity increasing gradually by concentration, until at the
present time the water has a specific gravity of 1*0076 (the
sp. gr. of sea water being 1*027).

Besides common salt the water contains appreciable quantities
of sodium sulphate and magnesium sulphate, carbonate and
bicarbonate, so that it is alkaline as well as brackish, and this
no doubt accounts for the very peculiar and remarkable Rotif erous

58 C. F. ROUSSELET ON THE ROTIFERA OF DEVILS LAKE

fauna it contains, which is abundant in numbers but very re-
stricted in species.

Since 1910 a Biological station has been established on the
shores of the lake by the Legislative Assembly of the State of
North Dakota, under the control of the Biological Staff of the
State University.

At the request of Prof. R. T. Young I have at various times
examined samples of plankton collected by him in July 1910 and
May 1912, and have found therein only the following seven
species of Rotifera, the majority of them rare, strange and
unusual forms :

Triarthra longiseta Ehrenberg (a single specimen, possibly

accidental).
Pedalion fennicum Levander. {Very abundant.)
Asplanchna Silvestrii Daday. (Very abundant.)
Brachionus Midleri Ehrenberg. (Few.)
Brachionus satanicus Rousselet. (Very abundant.)
Brachionus spatiosus Rousselet. (Very abundant.)
Brachionus pterodinoides sp. nov. (Few.)

Two of these forms I have already described as new,* and
have now to introduce a third still stranger species.

The single specimen of Triarthra may have been introduced by
accident in one of the tubes.

Rotifera are essentially freshwater animals, and brackish or
salt water does not suit the great majority of species; this ex-
plains the paucity of species living in Devils Lake.

This fact does not militate against the theory of cosmopolitan
distribution of the class, on the contrary it confirms it, for
Pedalion fennicum is known from brackish lakes only in Finland,
Egypt, Central Asia, Asia Minor, etc. The presence in the lake
of the rare Asplanchna Silvestrii suggests that the " Lago di
Villa Rica," in Chile, from which it was first obtained, is a
brackish lake. Perhaps Prof. Silvestri, who obtained Daday's

* Journ. Q.M.C., Ser. 2, Vol. XL, pp. 162 and 373 (April 1911 and 1912).

WITH DESCRIPTION OF A NEW BRACHIONUS. 59

material, would be good enough to confirm or disprove this
suggestion.

Brachionus pterodinoides sp. nov. (PI. 6, fig. 1).

This new Brachionus, of which only very few specimens were
found, possesses a type of lorica new to the genus, and appears to
have done its best to try to deceive the systematic student by
making itself look as closely as possible like a Pterodina. For quite
a considerable time I was unable to decide whether the animal
belonged to the genus Brachionus or Pterodina until I found one
specimen with the foot and its two small toes protruding, which
decided the question. As will be seen on referring to PI. 6, fig. 1,
the lorica is nearly circular in shape, greatly compressed and
flattened dorso-ventrally, and possesses a foot-opening situated
just below the middle on the ventral plate, a most unusual
situation for a Brachionus, but usual in Pterodina. The dorsal
plate of the lorica is greatly extended posteriorly beyond the
foot-opening, and under this projecting cover the eggs are carried.
The lorica is smooth except anteriorly, where six small ridges
mark the continuation of the six frontal spines. The mental
edge is a nearly straight line and without indentation. As far
as could be made out in the few preserved specimens available,
the internal anatomy of this species appears to be normal. In
one specimen the wrinkled foot was extended, showing two small
pointed toes, as shown in fig. \c. The lateral antennae protrude
high up above the middle on each side.

I am greatly indebted to Mr. F. P. Dixon-Nuttall for the
three figures giving an excellent idea of the form of this new
species and new type amongst the Brachionidae.

Size of lorica, length 285 /x (l/89th inch), width 224 fi (1/1 14th
inch).

Brachionus satanicus Rousselet (PI. 6, fig. 2).

When describing this species two years ago * I had specimens
only which had been obtained in a plankton collection made in

* Journ. Q.M.C., Ser. 2, Vol. XI., p. 162 (1911).

60 C. F. ROUSSELET ON THE ROTIFERA OF DEVILS LAKE

Devils Lake in the month of July 1910, and all these had the
shape shown in the figure, with two long, curved and widely-
separated posterior spines. Last year I obtained from Prof. Young
a collection made in the month of May 1912, much earlier in the
season, when the weather in North Dakota is still cold and the
water chilly. Together with the fully developed forms in this
collection I found a much smaller form, with short posterior
spines, curved inwards and other unusual features as represented
in PI. 6, fig. 26-/. The six frontal spines and the mental edge
are identical with those of the larger specimens, but the shape of
the body and the form and size of the posterior spines are very
different, and, strangest of all, the foot-opening is situated on the
postero-dorsal side of the lorica, a quite unheard-of position in
this genus. My first impression was that these were young
animals just hatched from eggs, but this is evidently not so, for
some specimens were seen carrying their eggs at the base of the
foot on the dorsal side, and they were therefore adults reproducing
freely. I can only conclude that this represents a case of
dimorphism, possibly a winter form which gradually, in successive
generations, transforms itself into the larger form with extended
and expanded posterior spines. In saying this I do not mean
that the smaller forms (PI. 6, fig. 26-c) can themselves grow into
the form of fig. 2a, but that their offspring will in a few genera-
tions more and more resemble the larger form. Intermediate
forms between the two types figured were not seen. In order to
follow up this transformation it will be necessary to obtain
plankton collections made about twice a month throughout the
year, which at present are not available. It certainly is not
easy to see how the dorsally situated foot-opening can change
into the median posterior position of the larger form, but it is
known that in the case of some Asplanchna (A. amphora,
A. Sieboldii) the transition from humped into saccate forms and
other changes take place suddenly, from one generation to the
next, produced apparently through a change of diet and
temperature, as shown by the recent researches of Dr. Arno

WITH DESCRIPTION OF A NEW BRACHIONUS. 61

Lange * and Prof. Powers. t Should these changes in B. satanicus
be confirmed, it will be the first record of true dimorphism in the
genus Brachionus. Fig. 2e and f represent variations in the
shape of the posterior spines of the smaller form.

Fig. 2a-f were drawn from my own preparations by Mr. F. R.
Dixon-Nuttall, to whom I am greatly indebted for these accurate
and beautiful drawings.

The large form fig. 2a measures 408 /x (l/62nd inch), and
the small form 250 /x (1/1 00th inch), in both cases including
the posterior spines.

Asplanchna Silvestrii, Daday.
PI. 5, figs. 19.

This fine and rare species was first described by Daday in
1902,J and found by him in plankton collections made by
Dr. Silvestri in 1899 in the Lago di Villa Rica in Chile. I have
not been able to ascertain if this lake is brackish or not,
Prof. Daday having no information on this point, but the
presence therein of Pendalion fennicum seems to make it highly
probable, for the latter species has never yet been found in
fresh water.

In the collections from Devils Lake I found Asplanchna
Silvestrii in great abundance, and moreover it presented a marked
dimorphism, and even polymorphism, for all gradations from
plain saccate forms to fully developed double-humped animals
were represented in the same gathering. PI. 5, figs. 1 4
represent three of the forms. It is not possible for me to say
w T hich of these forms appears first, or which is hatched from the
resting-egg, and what causes these changes of form. According
to the observations of Prof. J. H. Powers, of Nebraska Univer-

* Zur Kenntnis von Asplanchna Sieboldii, Zool. Anz. Bd. 38, pp. 433-441,
November 1911.

f A case of Polymorphism in Asplanchna simulating mutation.
American Naturalist, Vol. XL VI., 1912.

\ Beitrage zur Kenntnis der Siisswasser Mikrofauna von Chile. Ter-
meszetrajzi Fiizeteh, 1902.

62 C. F. ROUSSELET ON THE ROTIFERA OF DEVILS LAKE

sity, who has lately published an account of similar changes
in A. amphora found by him in a brackish pool, it is caused by a
change of diet, from vegetable to more substantial animal food,
and even cannibalistic fare. Prof. Powers found that the
animals hatched from resting-eggs were invariably saccate, and
that the humped and larger campanulate forms developed from
these.

Asplanchna Silvestrii is a very large and powerful animal, as
is shown by its ability to capture, swallow and digest the
large and vigorous Diaptomus which abound in this lake ; one
of these Copepods was seen to more than fill its stomach.

The male was also found ; it is humped, but the side humps
are not bind as in the humped female, as shown in figs. 5
and 6 ; the fertilised resting-egg is represented in fig. 9. The
jaws are of the usual type, but are different from those of any
other species of the genus, as is shown by fig. 7. The rami
are massive, and have a semi-circular cut-out near the tip,
which is peculiar ; they have also a strong basal hook and
median inner tooth. One of the rami, the one on the right
side when the basal hooks are uppermost, has a broad flange
near its apical tooth ; this serves as a stop for the opposite
tooth to prevent the two rami overlapping and interlocking.

The prominent lateral humps differ markedly from those of
other humped species, such as A. Sieboldii and A. amphora. In
A. Silvestrii these are bifid, having a constriction, more or less
pronounced, above the middle of the hump, giving it a double
rounded outline (fig. 1) ; on the dorsal side there is a pointed
hump near the middle of the body (fig. 2). In intermediate
forms the humps are less prominent until the purely saccate
form is reached (fig. 3), which in shape does not much
differ from that of A. Brightwelli. Prof. Powers has shown
that no single animal goes through these various shapes ; they
are born with the shape they possess and do not change it in
their lifetime, but their jDrogeny may have a different shape
from the parent. A young humped individual may be seen in

WITH DESCRIPTION OF A NEW BRACHIONUS. 63

the uterus of a saccate female. The change takes place more
or less suddenly from one generation to the next. The general
anatomy of A. Silvestrii follows that of other allied species,
and but few points need be mentioned. The two gastric glands
are large and kidney shaped, and are attached to the long and
rather wide oesophagus. The stomach has the usual structure
of large, dark-coloured granulated cells. The ovary has the
form of a narrow horseshoe-shaped band with a single row of
germ cells. An enlarged view of one of the lateral canals
with the contractile vesicle is given in fig. 8. The flame cells
are closely set and numerous, numbering over thirty ; the fine
tube to which they are attached adheres for some distance
to the nerve-thread of the ventro-lateral antenna on each
side.

The sense organs consist of three pairs of antennae, namely
two on the front of the head, two dorso-lateral and two
ventro-lateral in position, each ending in a rocket-shaped organ
with a tuft of stiff hairs on the outside. Two finger-like,
fleshy processes are seen, one on each side of the head close
to the corona. Daday mentions that the animal has three red
eyes, but I could discover only a single small cervical red eye,
situated on the small brain.

The male (figs. 5 and 6) is of usual structure, and has two
lateral humps, like the male of A. amphora.

Greatest size of female 1,150 /x (l/22nd inch) in length ; male
408 jx (l/64th inch) ; jaws 164 fx (l/155th inch) ; resting-egg
195 /x (1/1 20th inch) in diameter.

I am greatly indebted to Mr. Hammond for the excellent
figures of A. Silvestrii on Plate 5.

It is quite possible that farther plankton collections, and
particularly collections made amongst the aquatic vegetation
near the shores and in the bays of Devils Lake, may reveal
additional species of Rotifera, but a great crowd of freshwater
forms cannot be expected to inhabit this brackish and alkaline
lake.

64 C. F. ROUSSELET ON THE ROTIFERA OF DEVILS LAKE.

Explanation of Plates 5 and 6.

Plate 5.

Fig. 1. Asplanchna Silvestrii Daday, characteristic female with

double humps, dorsal view, x 50.

2. A. Silvestrii, side view, x 50.

3. A. Silvestrii, saccate form, dorsal view, x 50.

4. A. Silvestrii, intermediate form, ventral view, x50.

5. A. Silvestrii, male, side view, x 68.

6. A. Silvestrii, male, dorsal view, x 68.

7. A. Silvestrii, the jaws, x217.

8. A. Silvestrii, vascular system with contractile vesicle,

x 150.
9. A. Silvestrii, resting-egg, x 65.

Plate 6.

Fig. la. Braehionus pterodinoides sp. nov., dorsal view, x 196.
,, lb. B. pterodinoides, ventral view, x 196.
lc. B. pterodinoides, side view, x 196.
2a. Braehionus satanicus Rousselet. Normal type, x 180.
2b. B. satanicus, small seasonal form (winter), dorsal view,

X180.
2c. B. satanicus, small seasonal form (winter), ventral view,

Xl80.
,, 2d. B. satanicus, small seasonal form (winter), side view,

X 180.
2e. B. satanicus, small seasonal form (winter), variation in

posterior spines, x 200.
,, 2f. B. satanicus, small seasonal form (winter), variation in

posterior spines, x 200.

Joum. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913.

Journ.Q.M.C.

Ser. 2,Vol.Xir,Pl. 5.

3

^-Xr"-'

1

* .

9

A. R. Hammond del.et lith.. West,>4ewma.n imp.

As plan elm a Silvestrii Dadcuy.

Journ.QM.C.

Ser. 2,Vol.XII.Pl. 6.

la

/

lb.

F.R. Dixon -Nuttall del.adnat.

A.R.Hammond lith..
West, Newman, imp.

Rotifera.

65

THE PRESIDENT'S ADDRESS.

BY-PRODUCTS OF ORGANIC EVOLUTION.

By Prof. Arthur Dendy, D.Sc, F.R.S.

{Delivered February 25th, 1913.)

Plate 7.

We are all familiar with the fact that in the manufacture

of any particular product of human industry the raw material

employed is rarely entirely used up, a more or less considerable

*

residue generally remaining over after the process is completed.
In so far as the prime object of the manufacturer is to produce
some one special product, the residue which cannot be employed
for this purpose must be regarded as waste. It frequently
happens that this waste product is a highly deleterious substance,
the difficulty in the disposal of which may constitute a very
serious obstacle to the successful prosecution of the industry in
question. On the other hand, it also frequently happens that
what were primarily waste products may prove to have a value
of their own quite apart from the main object at which the
manufacturer is aiming. They then cease to be merely waste
products and become valuable by-products, perhaps even more
valuable than the main product itself.

Thus in the distillation of coal in a gasworks the main purpose,
that for which the machinery and apparatus are primarily
intended, is the production of gas, but coke and tar and other
by-products are also produced, all of which are now, I suppose,
applied to some useful purpose, and thus have a value of their
own. Indeed the existence of coal-tar has given rise to a whole
series of new industries, involving the production of almost endless
substances, such as the wonderful aniline dyes and so forth,
which many people will regard as far more valuable and desirable

Jourx. Q. M. C, Series II. No. 72. 5

66 the president's address.

objects than the gas for the sake of which the coal was originally-
distilled.

The value of a by-product will naturally depend upon the
particular circumstances of the case, and what is useless, or
even harmful, under one set of conditions may be extremely
valuable under another. It may be a question of labour supply
or of transport, or it may be that the discovery of some new
process of manufacture in a totally different industry suddenly
creates a demand for a by-product that was previously almost or
entirely worthless. It is perhaps not too much to say that the
success or failure of a manufacturer in his business must in
many cases depend upon the ingenuity that he exhibits in
disposing of his by-products ; but the formation of such products
in the first instance cannot be avoided, and they may go on being
produced, and constitute a characteristic feature of the industry
for a long time, before some new factor in the circumstances of
the case may give them a special value of their own. It may
well be that this may never happen at all, and the substances
in question may simply accumulate in harmless, if unsightly,
heaps, or, on the other hand, they may become so offensive,
or even dangerous, as to render impossible the continuance of
the industry which gives rise to them.

In short, it would be difficult to exaggerate the importance
of the part played by by-products in the evolution of human
industries. Such industries are necessarily subjected to a severe
struggle for existence in ceaseless competition with one another,
and in this struggle the by-products afford abundant opportunity
for the elimination of the least fit by the process of natural
selection. The by-products, however, did not themselves arise
through any process of selection, but as the unintentional and
inevitable results of those chemical and physical changes which
accompany the manufacture of the main product.

We may thus look upon a human industry as an organism,
which undergoes a process of evolution subject to the control
of natural selection, and some of the most characteristic features
of which are to be found in its by-products. Indeed it may
often be recognised and identified by its by-products almost if
not quite as readily as by the product for the sake of which
it primarily exists.

We must not, of course, push our analogy too far, but I hope to

THE PRESIDENT'S ADDRESS. 67

be able to convince you that in the evolution of living organisms
themselves by-products have played a part not unlike that which
they have played in the evolution of industries.

You have probably already began to wonder why I should
have chosen such a subject as this for an address to a micro-
scopical club ; but the reason will now become apparent, for
I propose to endeavour to elaborate the ideas which I have
been suggesting to you by reference to organisms which have
long been favourite subjects with the microscopist, and to
characters which can only be investigated with the aid of the
microscope.

We shall perhaps find nowhere in the animal kingdom a more
exact analogy to the utilisation of waste products in human
industries than in the curious rotifer Melicerta janus. As
you are all aware, this minute but highly complex organism
builds for itself a beautiful dwelling-place out of pellets of its
own dung. I do not, however, propose to dwell upon such cases
as this, and for our present purposes I must ask you to allow
me to interpret the term waste products, or if you prefer it, by-
products for it is obvious that the two cannot be sharply
distinguished from one another in a less literal manner.

There is, in my opinion, no group of organisms better suited
for the illustration of the fundamental principles of organic
evolution than the Sponges. This arises from the fact that they
combine with an essential simplicity of structure an inexhaustible
variation in detail, and that this variation is to a very great extent
clearly and precisely expressed in the form of the microscopical
calcareous or siliceous spicules of which the skeleton is ordinarily
composed. Moreover, it appears that an unusual number of
connecting links have been preserved to the present day, so that
we are able to trace beautiful evolutionary series in the wonderful
spicule -forms of existing species.

Take, for example, the siliceous spicules which are so character-
istic of the Tetraxonida. These are probably all to be derived
from a primitive ancestral form or archetype (fig. 1) consisting
of four rays diverging at equal angles from a common centre,
like the axes which connect the angles of a regular tetrahedron
with its central point. The assumption of this regular geometri-
cal form by a non-crystalline substance like the hydrated silica,
or opal, of which these spicules really consist, is a very remarkable

68 the president's address.

fact, especially when we consider how very widely it is afterwards
departed from on most lines of spicule evolution. It has been
suggested that the equiradiate and equiangular tetraxon was
originally adapted to the interstices in a system of spherical
flagellated chambers arranged tetrahedrally. This seems probable
enough, but in any case we can safely take this form as our
archetype without indulging in speculations as to its origin.

If we now imagine one ray of our archetype becoming greatly
elongated we get a common form of " triaene " spicule known
as the " plagiotriaene " (fig. 2), with a long arm or " shaft "
and three short arms or "cladi," but still with all the angles
equal. If we imagine the angles which the cladi make with
the shaft to be increased, so that the cladi come to point forwards,
we get the "protriaene" (figs. 5, 5a); if the cladi extend at
right angles to the shaft we get the " orthotriaene " (fig. 3), and
if they point backwards we have the " anatriaene " or grapnel
spicule (figs. 4, 4a).

All these long-shafted triaenes are typically oriented with
the cladi at or near the surface of the sponge, and the shaft
directed centripetally inwards, so that the entire skeleton acquires
a markedly radiate arrangement. The cladi of the orthotriaenes
usually form a support for the dermal membrane at the surface
of the sponge, beneath which they are spread out tangentially,
and their efficiency as a dermal skeleton may be greatly increased
by their bifurcation (" dichotriaenes," figs. 6, Ga). In the case of
the protriaenes and anatriaenes the distal portions of the shafts,
bearing the sharp-pointed prongs or cladi, usually project for
some distance beyond the surface of the sponge, and in this
position they probably serve either to ward off the attacks of
enemies or to entangle minute organisms whose decomposition
may supply the minute organic particles upon which the sponge
depends for its food supply and which will be carried inwards
by the inflowing stream of water.

A still more remarkable modification is met with in the
" discotriaene," in which the shaft is reduced to a short peg
inserted in the middle of a flat disk formed by fusion of the
cladi. The entire spicule then assumes somewhat the form of
a carpet-nail. In the genus Discodermia we find these disco-
triaenes stuck close together all over the surface of the sponge,,
and forming an impenetrable mail-armour.

THE PRESIDENT'S ADDRESS. 69

In Stelletta vestigium, on the other hand, the cladi are reduced
to the merest vestiges, and some, if not all of them, may com-
pletely disappear, while the shaft remains greatly elongated
and forms practically the entire spicule (figs, la Id). Possibly
the simple " oxeote " spicules of this and allied species (fig. 8)
have arisen in this manner.

An altogether different line of evolution from the primitive
tetraxon archetype appears to have given rise to the typical
oxeote spicules (figs. 9, 10) of the monaxonellid division of the
Tetraxonida. Here two of the four rays of the primitive
tetraxon have probably entirely disappeared, while the remaining
two have become extended in a straight line with one another.
In the typical " stylote " (fig. 11) and " tylostylote " (fig. 12)
spicules probably only a single ray persists, so that the so-called
organic centre is situated at one end instead of in the middle.
In many species the oxea, styles or tylostyles become ornamented
with sharp spinose excrescences (fig. 13).

In most of the cases which we have so far considered it is
easy to see that we are dealing with adaptive modifications.
The orthotriaene, dichotriaene, protriaene, anatriaene and
discotriaene are all obviously well suited for the fulfilment of
their specialised and differentiated functions, and the evolution
of these forms is more or less readily explicable in accordance
with the well-known principle of the natural selection of
favourable variations. The origin of the linear spicules of the
monaxonellid forms by complete suppression of two or three of
the rays of the primitive tetraxon is, perhaps, not so easy to
account for as is that of the triaene series from the same
starting-point. In both cases the determining factor was
probably, in the first instance, the development of a radially
arranged canal-system, requiring a corresponding radial arrange-
ment of the supporting skeleton, which could not be obtained
w T ith spicules of the primitive tetraxon form. That the evolu-
tion of the necessary linear spicules has taken place along
different paths in different cases is, however, nothing to be
surprised at ; it is merely one of those instances of convergence
which are quite as common amongst sponges as amongst other
groups of the animal kingdom.

In the most primitive tetraxonid sponges, which represent
more or less closely the ancestral forms from which both

70 THE PRESIDENT'S ADDRESS.

Tetractinellida and Monaxonellida have doubtless been derived,
we still meet with some of the earliest stages of spicule
evolution. Take, for example, Dercitopsis ceylonica, collected
by Prof. Herdman in Ceylon, and described in my report on
the Ceylon sponges. Here we find the tetraxon spicule in all its
primitive simplicity (fig. 25), but associated with it we get
numerous diact spicules (figs. 26a 26c), evidently derived from
the tetract by loss of two of the original rays, and clearly
showing, by a swelling or an angulation in the middle, that
two rays still remain. From such obvious diactine spicules as
these, transitional forms lead the way to the comparatively
large, straight oxeote spicules which occur in the same and in
many other sponges, and which no longer show any trace of
their tetraxon and tetract ancestry.

In Dercitopsis and its relations i.e. in the Homosclerophora
although there may be great differences as regards the size
of the various spicules, yet we cannot, as in most of the higher
groups, sort these spicules out into two distinct categories
megascleres and microscleres for innumerable gradations exist
between large and small.

In the course of further evolution, however, the distinction
between megascleres, or skeleton spicules, and microscleres, or
flesh spicules, becomes very strongly marked. Both have
doubtless had a common origin in the ancestral tetraxon
archetype, but whereas the former are obviously adapted as the
principal skeletal elements, and are arranged accordingly in
the sponge, the latter are usually scattered at random through
the soft ground substance like plums in a pudding, and neither
in form nor arrangement show any evident adaptation to the
requirements of the organism.

Indeed, the microscleres are usually so extremely minute,
requiring high powers of the microscope to make out their
true form, that is impossible to believe that their presence can
exercise any important influence upon the well-being of the
sponge. Still less is it possible to believe that the particular
shape which they may assume, which is often highly remarkable,
can be of any consequence to their possessor. There are, of course,
exceptions to this, as to every generalisation, and sometimes we
find microscleres forming a dense protective external crust, as
in the case of the " sterrasters " of Geodia, or projecting into the

THE PRESIDENT'S ADDRESS. 71

inhalant canals, where they may perhaps serve to filter the
incoming water and guard against parasites, as in the case of
the " sigmata " of Esp>erella murrayi ; but in the vast majority
of cases it is impossible to assign any value at all to the
presence of microscleres. Indeed, the numerous species of
horny sponges seem to get on quite as well without these
bodies.

Nevertheless we find that the microscleres, when present,
are characterised by very definite and constant forms, and many
of them are amongst the most beautiful and wonderful objects
that come under the observation of the microscopist. So constant
and characteristic are they that they afford by far the most
convenient and most reliable data for the classification of the
tetraxonid sponges. Particular species, and even particular
genera and families of these sponges, are characterised by the
presence of highly specialised forms of microscleres, and in the
case of species the characteristic form is almost invariable.

There can be no doubt that the microscleres have undergone
an evolution along definite lines, and one species of a genus is
commonly distinguished from another by differences in the
shape of these spicules, which, though constant, appear at the
same time to be utterly trivial as, for example, the difference
in the shape of the teeth at the small end of the " isochelae " in
Cladorhiza pentacrinus (figs. 23, 23a) and Cladorhiza (?) tridentata
(figs. 24, 24a). There may be several kinds of microsclere in
the sponge, all characteristic of the species, but a single sponge
may contain many thousands, or perhaps millions, of the same
kind, all exactly alike in shape and size except for an occasional
individual variation such as occurs in all organisms.

The shape of the microscleres appears to be quite independent
of their position in the sponge, and must obviously be attributed
to some specific peculiarity of the ovum from which the sponge
developed. It is clearly of a blastogenic and not a somatogenic
character, and it is usually much more remarkable and quite
as constant as that of the megascleres of the same species.

The microscleres of the tetraxonid sponges may be divided
into two categories, termed astrose and sigmatose respectively.
The former (figs. 14a 14A) may be derived from the tetraxon
archetype by multiplication of the rays due apparently to
meristic variation accompanied usually by diminution in size of

72 the president's address.

the whqle spicule ; at the same time the rays may become spiny
or branched in a variety of ways, or even soldered together to
form a solid siliceous ball (Geodia).

The sigmatose microscleres are more remarkable and more
constant in form. They are essentially linear spicules, and
appear to be derived from minute diactinal oxea. These may be
straight (" microxea," fig. 15) or bow-shaped (" toxa," figs. 16, 18a,
186), or their extremities may become bent over to form hooks
(" sigmata," figs. 17a, 176, 19). A very peculiar modification of
the sigmata is found in the " diancistra " (fig. 21), which often
resemble nothing so much as pocket-knives with the blades half
open. From the sigmata have also doubtless arisen the " chelae," *
characteristic of the family Desmacidonidae, and, in my opinion,
the most wonderful of all sponge spicules. Three different chelae
are shown in figs. 22 24a.

A typical chela consists of a curved shaft, bearing a number,
commonly three, of recurved teeth, resembling the flukes of an
anchor, at each end. The flukes are sometimes expanded into
thin blades, and so also may be the shaft. Sometimes the flukes
at the two ends of the spicule are equal in size (" isochelae,"
figs. 22, 22a), sometimes those at one end are larger than those
at the other (" anisochelae," figs. 23 24a), while in the genus
Melonanchora a very curious effect is produced by the meeting
and fusing of opposite flukes of an isochela at the equator of
the spicule. Minute differences in the form and number of the
flukes and the shape of the shaft appear to be constant, at any
rate within the limits of a species ; indeed, the very numerous
species of Desmacidonidae are to a large extent distinguished from
one another by these characteristics (compare figs. 23, 23a, and
24, 24a).

The same constancy of form is to be observed in the sigmata,
although here there is less scope for specific differences. In
both cases the spicule, instead of remaining smooth, may become
more or less roughened by the development of minute projections.
This is shown, for example, in the sigmata of the genus Par-
esperella (fig. 20), where a row of small projections, like the teeth

* It is perhaps unnecessary to discuss here the evidence for believing
that the chelae have arisen from sigmata. It is derived partly from the
development of the chelae themselves and partly from the occurrence of
intermediate forms.

THE PRESIDENT'S ADDRESS. 73

of a saw, occurs at each end of the shaft, just where it bends
round.

Now it appears to me quite idle to argue that minute differ-
ences in the form of the microscleres, such as I have just described,
are of any importance to the sponge in whose soft tissues these
microscopic spicules are scattered without order or arrangement.
Nevertheless they constitute, as I have already said, constant
specific characters, and have undoubtedly arisen by some process
of evolution, one form Lading to another just as in the case
of any other characters. Such characters are, of course, by no
means confined to sponge spicules ; they may be more or less
exactly paralleled, for example, in the frustules of Diatoms, the
shells of Foraminifera and Kadiolaria, and the calcareous spicules
of Holothurians. Natural selection cannot be directly respon-
sible for their origin. How, then, are they to be accounted
for?

Before attempting to answer this question let us inquire how
a microsclere actually arises in the sponge. It appears that,
from an early stage in embryonic development, certain cells,
known as scleroblasts, or mother-cells, are set aside for the
purpose of spicule-formation. These mother-cells have the power
of extracting silica in solution from the sea-water which circu-
lates through the sponge, and depositing it in the form of solid
opal, and in the particular shape characteristic of each spicule.
Each separate microsclere arises thus in the interior of a single
mother-cell. Let us examine a little more closely the conditions
under which it is deposited.

The mother -cell is, of course, a nucleated mass of protoplasm,
and it appears to be bounded on the outside' by a more or less
definite cell -membrane. The spicule, at any rate in the case
of sigmata and chelae, appears to be deposited on the inner
surface of this membrane, and this fact probably explains why
it is curved. If we assume, as seems probable, that the mother-
cell continues to grow while the spicule is being deposited, and
that the spicule is adherent to the cell-membrane, then we may
further suppose that the increasing tension and expansion of the
latter may cause the thin siliceous film to split into flukes or
teeth. Probably, then, the form of the spicule is largely due to
mechanical causes. We cannot, however, explain the minute
details of structure so simply as this, for why should the chela

74 the president's address.

of one species have always three flukes and that of another
always more ? Why should the two ends in some cases be equal
and in others unequal 1 Why should the teeth at the small end
sometimes be shaped as in fig. 23 and sometimes as in fig. 24 ?
and why should some be roughened with spines and others not ?
We must, I think, assume that these minute differences are
dependent upon minute differences in the constitution of the
protoplasm of which the mother-cell is composed. It may be
a question of the chemical and physical composition of the
cytoplasm in which the spicule is actually deposited, or it may
be that the nucleus exerts some direct controlling influence
upon the form of the spicule, of the nature of which we know
nothing.

At any rate we can hardly be wrong in attributing specific
differences of spicule-form to corresponding differences in the
constitution of the mother-cells by which they are secreted. The
remarkable thing is that such differences should be so constant,
not only throughout hundreds of thousands of mother-cells in
the same sponge, but throughout the mother-cells of all the
individuals of the same species. We can only suppose, as I said
before, that this constancy depends upon some constant peculiarity
of the germ-plasm from which all the cells of the individual and
all the individuals of the species originate. Obviously the ferti-
lised ovum must contain within itself the potentiality of pro-
ducing, amongst other things, all the different kinds of spicules
which may happen to characterise the particular species to which
it belongs. As development goes on differential divisions must
take place whereby all the different kinds of cells of which the
adult sponge is composed are segregated, and each mother-cell
must ultimately retain the power to secrete only one particular
kind of spicule. Now there is strong reason for believing that
differential cell-division is effected always by the complex process
of mitosis or karyokinesis, which concerns chiefly the chromosomes
of the nucleus, and hence I think we may pretty safely conclude
that specific differences in the form of the microscleres must
depend upon differences in the constitution of the nuclei of the
mother-cells, or, in other words, that the nuclei of the mother-
cells determine to a large extent the form of the microscleres.

There appear, in short, to be three secondary factors concerned
in the production of any particular form of microsclere : (1) the

THE PRESIDENT'S ADDRESS. 75

nature of the material (opal) of which the microsclere is com-
posed ; (2) the nature of the medium in which it is deposited,
viz. the colloidal cytoplasm of the cell ; and (3) the presence of
the cell-membrane, by which the growth of the spicule is to some
extent restrained and guided. All three are, however, doubtless
dependent upon the hereditary constitution of the mother-cell
(including, of course, its nucleus), for while the mother-cells in
siliceous sponges secrete hydrated silica, those of the Calcarea
secrete carbonate of lime, and so on.

We have next to inquire how it is that, if the specific forms
of sponge microscleres are of no importance to the sponge, such
very remarkable forms should ever have arisen in the course
of evolution. We have to remember in this connection that we
are dealing not merely with a few isolated and unrelated forms,
but with progressive evolutionary series along lines as definite
as any other lines of evolution with which we are acquainted,
and which certainly seem to require some directive force to
explain them. If we were dealing with adaptive characters we
should at once say that the result was due, as in the case of the
megascleres, to the natural selection of small, fortuitous, favour-
able variations ; but the fact that the characters in question are,
for the most part at any rate, not adaptive, seems, at first sight
at any rate, to rule natural selection out altogether.

It might be suggested, however, that the solution of the
difficulty is to be found in the well-known principle of correlation.
In accordance with this idea certain characters of an organism
are inseparably linked together with other characters in such
a way that any variation in the one must be accompanied by
a corresponding variation in the other, though the reason why
such characters should be so linked together is often by no means
obvious. To upholders of such a view as this the analogy of
by-products, upon which I laid so much stress at the beginning
of my address, may, I think, prove useful. Although I doubt
whether the hypothesis of correlation is adequate to meet the
present case completely, it certainly seems worth while to
examine it a little more closely.

I may illustrate my meaning by reference to the action of a
few drops of acid upon an alkaline solution of litmus. Two per-
fectly distinct results will be produced. The solution will become
acid and it will change from blue to red. You may desire for

76 the president's address.

some special purpose to produce one of these results only, but
they are inseparably connected and you cannot have one without
the other. You cannot have the result aimed at without having
also the by-product.

Now suppose some change in the constitution of the germ-
plasm of an organism to give rise to two modifications in the
developing soma or body. We may call the change or modi-
fication in the germ-plasm GA and the modifications in the soma
SA and Sa. SA and Sa will be inseparably correlated with one
another through GA, though as for example in the case of
white tom-cats with blue eyes, which are said to be generally
deaf the connection between them may appear to be quite
arbitrary.

Suppose further that SA proves to be a useful character and
Sa a useless one. Then, under the influence of natural selection,
SA will be preserved and may ultimately develop into a very
perfect adaptation ; but, if so, GA must also undergo further
modification, and this modification will likewise affect Set, which will
therefore keep pace, so to speak, with SA. Thus a non-adaptive
character (S) may undergo progressive evolution, which, though
in reality indirectly controlled by the action of natural selection,
may appear to be guided by some mysterious vital force or
entelechy.

Now suppose further that as a result of some change in
the conditions of life, or merely as the result of its progressive
evolution in some particular direction, So- in turn acquires some
value in the struggle for existence. Natural selection will, in
future, favour its further development directly, and what was
at first a mere by-product becomes an adaptive character. Thus
adaptive characters may perhaps become linked together in
groups, the existence of each group being dependent on some
particular property of the germ-plasm through which all the
members of the group are connected.

At the same time non-aclaptive characters may persist side
by side with adaptive ones, and even harmful variations may
persist if their injurious effects are counterbalanced by useful
characters with which they happen to be correlated and which
cannot exist without them. Inasmuch, however, as two useful
characters are more valuable than one, natural selection will
tend to favour the correlation or linking together of adaptive

THE PRESIDENT'S ADDRESS. 77

characters, and this is perhaps the reason why, in the higher
organisms, non -adaptive characters are less frequently met with
than in lower forms. Moreover, the effect of natural selection
will tend to become cumulative and the rate of evolution corres-
pondingly increased.

It may be objected that even in the highest organisms
characters often vary independently of one another, but who
knows how many characters are really involved in each such
variation ? Moreover, it by no means follows from what has
been said above that new characters, whether valuable or
otherwise, may not arise singly and remain quite independent
of others.

In any case the principle of correlation could hardly help us
to explain the specific forms assumed by sponge microscleres, or
indeed the exact nature of any non-adaptive character ; it could
only help to explain why such characters should exist at all and
why they should undergo progressive evolution.

If it be asked, what are the adaptive characters with which,
in our own particular case, the non-adaptive characters of
the microscleres are supposed to be correlated ? it must be
admitted that this question cannot at any rate at present be
answered, but it would be sufficient for the general argument if
it were granted that a modification in the constitution of the
germ -plasm which gives rise to a useful character may at the
same time give rise also to a useless one, or perhaps even to
many useless ones.

The question, why are the specific forms of sponge microscleres
what they are 1 ? is probably one that will have to be answered,
if it ever is answered, by the chemist and physicist rather than
by the mere biologist ; or perhaps by that happy combination
of chemist, physicist and biologist whose advent is so much
to be desired. I have suggested that the form is probably
determined by the hereditary constitution of the mother-cell,
including its power to select silica as the raw material to be
worked up, but this is no more than to say that the nature of
the product turned out by a factory depends upon the character
of the work-people employed and of the machinery and raw
material with which they have to deal. In the case of our
microscleres we want to know a great deal more about the
nature of the machinery and the manner in which it is controlled

78 the president's address.

before we can hope to reach even an approximate solution of the
problem.

Some light may perhaps be thrown on the subject by ex-
periments such as those of Leduc and others upon artificial
osmotic growths. Leduc, in particular, has succeeded in pro-
ducing very interesting growth-forms by the osmotic action of
various chemical reagents in solution. Some of these forms bear
an extraordinary resemblance to the forms of living organisms.
I do not, of course, attribute much importance to the particular
forms produced in this manner as explaining the particular
forms of any living organisms. What they demonstrate is that
purely chemical and physical causes may give rise to more or less
definite and at the same time non -crystalline forms in colloidal
media, and though none of the forms as yet produced come
anywhere near our sponge-spicules in symmetry or sharpness of
definition, they certainly seem to indicate a hopeful line of
inquiry. The particular form produced depends upon the nature
of the reagents employed and upon the conditions under which
the experiment is carried out. If these always remain constant
we may assume that the osmotic growth will always have the same
form, but probably with the means at our disposal it would be
impossible to produce exactly the same result twice over. The
remarkable thing about the sponge microscleres is that within
the limits of the same species the same results very often are
exactly reproduced, or at any rate so exactly that we are unable
to distinguish between them. I suggest that these results are
produced by chemical and physical causes, involved in and
controlled by the hereditary constitution of the mother-cell,
and that any modification of this hereditary constitution must
give rise to a corresponding modification in the results. Further
than this I fear we cannot at present venture.

It has frequently been objected to the theory of natural
selection that, however much useful characters may be en-
couraged and fostered in the struggle for existence, it cannot
account for the first appearance of such characters. This appears
to me to be a very fair criticism. It seems to me, also, very
misleading to speak of the origin of species by natural selection,
for specific characters throughout the animal and vegetable
kingdom are, I believe, generally non-adaptive, and therefore
cannot be directly due to natural selection. This is certainly the

THE PRESIDENT'S ADDRESS. 79

case with the specific characters of sponges, which, as we have
seen, depend for the most part upon trivial microscopical differ-
ences in the shape of the spicules.

Without entering upon the vexed question of the relation
between somatogenic and blastogenic characters, we may assume
in our ignorance that such characters as those which we have
been discussing arise fortuitously in the germ-plasm, and that
it is a mere chance whether or not they may prove to be of any
value to the organism. If they are valuable, natural selection
will foster and encourage them ; if they are not, they may
nevertheless persist for many generations unless too injurious to
their possessors. If linked by correlation with useful characters
they may be indirectly fostered by natural selection, and un-
dergo a course of evolution parallel to that of their correlative
characters. Although they may be useless at first, they may
acquire some special value under new conditions of life, or in
the course of their evolution under the old conditions, and then
natural selection will begin to act upon them directly.*

Possibly all the characters which an organism exhibits, with
the important exception of those which are due to the effects
of use and disuse of organs, or to the response of the
organism in some other way to the direct action of the environ-
ment, have first arisen as by-products of the complex chemical
and physical processes upon which the life of the organism
depends.

There is one more aspect of the problem to which I should like

* Having been asked to give a definite example of a character which,
at first useless, has ultimately acquired an adaptive value, I suggest the
pattern of the venation on the front wings, or tegmina, and on the leaf-like
outgrowths of the abdomen in the leaf-insect Pulchriphyllium cvurifoliuvi.
This venation so closely resembles that of a leaf as greatly to increase
the remarkable protective resemblance which undoubtedly enables the
insect to conceal itself effectively from its enemies. The mere pattern
of the venation in the more primitive and typical Orthoptera can hardly
have had any selective value. Of course the venation itself must always
have been useful, both for supporting the wings and for supplying them with
air, etc. ; but as regards the pattern which the venation makes (which is
the character to which I refer) one type of arrangement would seem to
have been as good as another until it acquired a special adaptive value
as a factor in bringing about protective resemblance to a leaf, and then
doubtless the pattern evolved under the influence of natural selection until
it reached its present degree of perfection.

80 THE PRESIDENT'S ADDRESS.

to direct your attention before concluding. The constancy in
the specific form of the microscleres of the Tetraxonida appears
to be much greater in the case of the sigmatose than in that of
the astrose series, and in the former at any rate seems to point
to the different modifications having arisen as mutations rather
than as fluctuating variations. This would, I think, be quite
in harmony with the views which I have been endeavouring to
express. A mutation, however small it may be, is believed
to be due to some change, apparently sudden, in the constitution
of the germ-plasm, which may then remain without further
alteration until another mutation occurs. To say that the
change in question is probably of a physico-chemical character
seems almost a truism ; but if it is so it seems only natural to
suppose that such a modification, transmitted by cell-division
to all the mother-cells of a particular kind, may affect in a
uniform manner the form of all the microscleres deposited in
these mother-cells, just as a change in the character of the
reagents employed will affect the form of osmotic growths ex-
perimentally produced. If this view be correct, we must suppose
also that any adaptive modifications with which the modifications
of the microscleres may possibly be correlated must also have
arisen as mutations. I see no objection to such a supposition,
for mutations, if they occur sufficiently frequently, may be quite
as valuable from the point of view of natural selection as small
fluctuating variations.

We do not, of course, know what may be the cause of the
modification in the constitution of the germ-plasm that gives rise
to a mutation, but there is some reason to believe that it may
be due either to the permutations and combinations of ancestral
characters which take place in the maturation and fertilisation
of the germ-cells, or to the influence of some change of environ-
ment upon the germ- plasm. If the characters of sponge spicules
are really of the nature of mutations it should be possible to
obtain Mendelian results by hybridisation, and I hope that
at some time in the future experiments may be made with this
object in view. The difficulties in the way of carrying out
such experiments would probably, however, be very great, and
we should require to know a great deal more than we do about
the breeding habits and life-history of sponges before we could
hope to bring them to a successful issue.

33
33
33
3)
33
33
33

THE PRESIDENT'S ADDRESS. 81

Description of Plate 7.

Fig. 1. Ideal primitive tetraxon.

2. Plagiotriaene of Ecionema carteri, x 52.

3. Orthotriaene of Pilochrota homelli, X 52.

4. Anatriaene of Tetilla poculifera, X 52.
4a. Cladome of 4 x 230.

5. Protriaene of Tetilla pocidifera, x 52.
5a. Cladome of 5 x 230.

6. Dichotriaene of Ecionema laviniensis, x 52.
6a. Cladome of 6, seen from above, x 52.
,, la-Id. Ends of triaenes of Stelletta vestigium, with reduced

cladi, x 230.
,, 8. End of oxeote of Stelletta vestigium, x 230.
,, 9. Angulated oxeote of Pachychalina subcylindrica, x 360.
10. Straight oxeote of Reniera pigmentifera, x 360.
,, 11. Style of Axinella halichondrioides, x 230.
12. Tylostyle of Hymedesmia curvistellifera, X 230.
13. Spined tylostyle of Myxilla tenuissima, x 530.
,, 14a-14A. Astrose microscleres of Xenospongia patelliformis,

X 530.
15. Microxeote microsclere of Desmacella tubidata, x 230.
16. Toxiform microsclere of Gellius angulatus var. canalicu-

lata, x 230.
17a, lib. Sigmata of Gellius angulatus var. canalicidata, x 230.

(Note the angulation of the spicule, suggesting

derivation from a diactinal microxeote, such as is

represented in figs. 26a-26c.)
18a, 186. Toxa of Toxochalina robusta var. ridleyi, X 230.

19. Sigma of Desmacidon reptans, X 512.

20. End of sigma of Paresperella serratohamata, x 530.

21. Diancistron of Vomerula or Hamacantha, x about 200.

22. Isochela of Esperiopsis pulchella, front view, x 284.
,, 22a. Side view of same, x 284.

23. Anisochela of Cladorhiza jientacrinus, front view, x 700.
,, 23a. Side view of same, x 700.
24. Anisochela of Cladorhiza (?) tridentata, front view,

x 360.
24a. Side view of same, x 360.
Journ. Q. M. C, Series II. No 72 6

35
33
33
J3

82 the president's address.

Fig. 25. Primitive tetraxon (calthrops) of Dercitopsis ceylonica,
x 230.
26a-26c. Small oxea of Dercitopsis ceylonica, x 230. (Oxea
four or five times as large occur in the same
sponge.)

(Figs. 2-186, 20, 25-26c, from Dendy's Report on the Sponges
collected by Prof. Herdman at Ceylon in 1902. Figs. 19, 21, 22,
22a, 24, 24a, from Ridley and Dendy's Report on the Challertgo
Monaxonida. Figs. 23, 23a, from Dendy in Ann. <& Mag. Nat.
Hist., Ser. 5, vol. 20, PI. xv.)

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913.

Journ.dM.C

Ser.2yol.XlI

Spicules of Tetra-xorud Sponges.

83

ON FIVE NEW SPECIES OF BDELLOID ROTIFERA.

By David Bryce.

{Read March 2oth, 1913.)

Plates 8 & 9.

The five species of which descriptions are furnished in the present
paper have been known as distinct forms for many years past,
although their distinguishing characteristics have not hitherto
been gathered into the formal diagnosis which constitutes scientific
baptism. Four of them belong to that important section of the
Philodinidae in which the food is formed into pellets after passing
through the mastax, and are assigned to the genus Habrotrocha.
The fifth species belongs to the more numerous section of the
same family in which the food is not at any time agglutinated
into pellets, and being oviparous and possessed of three toes is a
member of the genus Callidina, as now restricted.

Under the name of Habrotrocha munda, I describe the form to
which T referred in some remarks upon the identity of Callidina
elegans Ehrbg., appended to my paper on " A New Classification
of the Bdelloid Rotifera," * as having been wrongly identified as
that species by Hudson and Gosse and by other writers. I have
endeavoured in that place to show as clearly as possible my
reasons for the belief that this form cannot be that which Ehren-
berg described ; and inasmuch as none of the various correspondents
who have addressed me with regard to my classification have
advanced a view contrary to my own in this matter, I think
that this victim of mistaken identity may now be established on
a firmer and less assailable basis.

This species is the most common of the few pellet-making forms
which have their usual habitat in ponds and ditches. In fresh
gatherings it may frequently be seen swimming vigorously with
its head slightly deflexed, or perhaps marching about at a great

* Jaimi. Q. M. C, Ser. 2, Vol. XI., p. 61.

84 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA.

pace, and will often attract attention from the bright reddish
colour of the stomach wall. On closer examination it may be
readily recognised from the peculiar shape and pose of the spurs,
which are quite distinctive, and from the many-toothed rami.
Under more natural conditions, it takes shelter in any convenient
recess among debris or in leaf axils, and there makes its home,
protruding the head and neck when it desires to feed.

The second species, Habrotrocha torquata, has similar many-
toothed rami, but in several other respects differs distinctly from
H. munda. I believe that in some quarters it has also been
accepted as Callidina elegans Ehrbg., probably on account of the
rami. Unlike H. munda, it is never found in ditches or ponds,
but has its habitat usually in mosses growing in positions fre-
quently wet. The spurs are of simple form and the stomach wall
is never of reddish tint. It has not been observed to seclude itself
in any way and is of comparatively quiet habit. Its specific
name was suggested by a curious but illusory appearance in some
positions of an annulus encircling the expanded corona.

The third of the pellet-making species, Habrotrocha spicida, is a "
rather smaller form, which has the, so far, unique distinction of a
single spine of small size placed on the pre-anal segment on the
median dorsal line. When the body is contracted, or when the
animal is seen in lateral view, this spine is sufficiently obvious,
but at other times it is most easily overlooked. In my own
experience this Bdelloid has only occurred in hilly country in
elevated positions, but I learn from Mr. James Murray that he
has also met with it in lowland habitats.

The fourth species, Habrotrocha ligida, is one of those puzzling
forms which can only be recognised with certainty when it is feed-
ing. It is mainly distinguished by the possession of a small fleshy
tooth, which stands erect in front of the narrow sulcus between the
two pedicels of the corona, difficult to discern except in direct dorsal
view. In other respects it offers little to remark.

For my earliest knowledge of the new Callidina, I am indebted
to my esteemed correspondent the late Forstmeister L. Bilfinger,

D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 85

of Stuttgart, who sent to me, as long ago as 1894, a sketch of the
animal together with some moss in which it occurred. I have
therefore given it the specific name Bilfingeri, in honour and in
grateful appreciation of a most courteous correspondent and of a
painstaking and careful observer of the Rotifera. The type form
of this species is marked by a series of lateral and dorsal knob-
like prominences on the posterior half of the trunk. As in most
other species with such knobs or with spines, the presence of these
ornaments is not constant, and occasional examples are found in
which some or even all the typical prominences are absent.

Habrotrocha munda sp. no v. (PI. 8, fig. 1).

Specific Characters. Corona moderately wide, exceeding collar ;
pedicels with dorsal inclination ; discs more strongly inclined in
same direction. Under lip relatively high, centrally prominent
and spoutlike, Dorsal antenna long. Rami with seven or
more fine teeth. First foot joint with dorsal prominence. Spurs
resembling caudal processes of Chaetonotus.

In general build and in the somewhat " smothered " appearance
of the corona, due in this case to the shortness of the pedicels and
to the very oblique setting upon them of the trochal discs, this
species has a certain resemblance to Habrotrocha torquata, but
can usually be distinguished from it by the shape of the spurs,
which in typical specimens have a very characteristic moulding
and pose. In the normal or extended position, the body is spindle-
shaped, distinctly larger about or a little behind the centre, and
smaller at either extremity, and rarely exceeds 320 /x in length.
While the rostrum is shorter and thicker than usual, the head
and neck are only moderately stout, the trunk being distinctly
larger (sometimes almost swollen when well fed), the lumbar
segments short and tapering rapidly to a relatively small and
slender foot of (I think) three segments. When creeping, the
dorsal and lateral longitudinal skin-folds are usually well marked.
In adult examples the stomach wall is frequently of a vivid
reddish colour, and the lumen of the stomach is usually crammed

86 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA.

with obvious food pellets. The first foot segment has a median
dorsal prominence of moderate height, rather wider than long,
and best seen in lateral view. The second segment has the very-
characteristic spurs, which always suggest to me the caudal
processes of the common form of Chaetonotus. They are longer
than is customary among pellet-making species, frequently
measuring 14 to 15 /x in length, but are sometimes much shorter.
Near the base they are swollen on the inner side, and closely
approximate. About mid-length they suddenly diminish in
thickness and are thence produced to rather acute points. The
outer side of each is nearly straight, and they are held at a
slightly divergent angle. The three toes are difficult to see, but
the terminal pair (and I think the dorsal toe" as well) are
moderately long and acute. The dorsal antenna is sometimes
quite 25 fx long and is carried much as in Rotifer macroceros t
being inclined backwards when the animal is creeping about, and
directed more or less forward when it is feeding.

The corona attains a width of about 45 li. The trochal discs
are separated by a shallow furrow, which narrows to a mere
notch as it nears the ventral side. On that side accordingly the
principal wreath is almost uninterrupted, and in place of the
customary appearance in front view of two distinct " wheels ''
there is rather that of a toothed band passing rapidly round a.
single transversely elliptic course, distinctly broken on the dorsal
side and only slightly indented on the ventral. In lateral view
it is seen that the pedicels are dorsally inclined, short and
obliquely truncate, so that the trochal discs are still more inclined
towards the dorsal side. The under lip and mouth margins are
high in relation to the discs, and the former centrally prominent
and spout-like as in Habrotrocha angusticollis, but in a lesser
degree. The upper lip is usually hidden by the reverted rostrum.
So far as I have been able to discern, it rises moderately towards
the centre and is neither bilobed nor reflexed. The rami are
about 19 fx in length, somewhat triangular in outline, and have
each at least seven very fine teeth.

D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 87

Habrotrocha munda occurs most frequently in pools, especially
when water-mosses and anacharis are present. I have also found
it occasionally in sphagnum and in confervae, both in floating
masses and in the growth upon submerged stones. In suitable
situations it makes for itself a rough case or nest of the same type
as that produced by Rotifer macroceros.

It is of cosmopolitan distribution. I have noted it for
England, Scotland, Germany (Baden, Black Forest, Wurtemberg,
Stuttgart), Cape Colony.

Habrotrocha torquata sp. nov. (PL 8, fig. 2).

Specific Characters. Of medium size and stoutness. Corona
equal to or rather exceeding collar ; pedicels short, distinct ;
trochal discs more or less dorsally inclined. Upper lip moderately
high, undivided but centrally slightly reflexed ; under lip
unusually high, yet scarcely prominent. Dorsal antenna rather
long. Kami with six or more fine teeth. Spurs short, divergent,
conical.

When creeping about, H. torquata is somewhat difficult to
recognise, as it lacks any conspicuous peculiarities of form, colour
or size. It is perhaps most usefully described by comparison with
other species of the same genus having similar many-toothed
rami. The body is of moderate dimensions, less spindle-shaped
than in H. munda, but less parallel-sided than in H. elegans
(Milne). The rather short foot is longer and more distinct than
in the latter species, but is less so than in H. constricta (Duj.).
The spurs are simple short cones of moderate stoutness, and are
held at almost a right angle, differing thus from the slighter and
widely divergent spurs of H. constricta, the short, peg-like, very
slightly divergent spurs of H. elegans (Milne) and the com-
paratively long moulded spurs of H. munda. In most examples
the stomach is not obviously tinted, but is occasionally of a
yellowish colour, yet never of the reddish shade frequent in
H. munda, H. auricidata, and other species.

In habit it resembles H. constricta ; that is to say, it lives in the

88 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA.

open and is not a dweller in the shelter afforded by natural or
contrived gatherings of dirt particles or debris like H. elegans
(Milne) and H. munda. I have never met with it in pools, but
usually in mosses (not sphagnum) growing in wet positions.
When the corona is displayed, it is seen to have a quite unusual
appearance. As in H. munda, the trochal discs are inclined
towards the dorsal side, but in a varying degree, and are
separated by a furrow deeper than in that species. The upper
lip rises in a broad rounded lobe which is centrally bent back,
leaving visible the fleshy connection, or nexus, between the short
pedicels. On the ventral side the under lip rises unusually high,
and thus in dorsal view, the collar, which passes round the
pedicels on either side and merges gradually into the under lip,
has an obliquely upward direction, not obliquely downward as
customary. This results in the optical presentments of the
rapidly beating cilia of the secondary wreath (those lining the
collar and passing round to the mouth), and of the cilia of the
principal wreath (those of the trochal discs), being to some extent
commingled, and there is the appearance of an annulus or ring
passing round the trochal discs immediately below their margins.
When the discs are seen so that their planes are nearly
coincident with the line of sight, they appear to have deeply
grooved margins, but the exact appearance varies with the angle
at which they are viewed. Whether the appearance be that of a
ring or of discs with deeply grooved margins, it is in my opinion
purely an optical effect arising from the mutual interference of
the light rays from the two wreaths of cilia.

The high under lip is unusually flat and inconspicuous ; the
lateral margins of the mouth are scarcely thickened and the
mouth cavity is small as compared with that of other Philo-
dinidae. When feeding the lumbar plicae are well marked.

The foot represents about one-ninth of the total length. It
has four joints, the first having dorsally a distinct thickening of
the hypodermis.

In the confinement of a small cell H. torquata proved only

D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 89

moderately hardy. After a few days, most specimens would
feed freely under the unaccustomed light and would remain
quiet, but I have never known eggs to be laid under such
conditions.

By no means a common species, yet widely distributed ; I noted
it first in moss sent me in 1895 by Forstmeister L. Bilfinger,
of Stuttgart. I have since found it in moss from Epping Forest,
Essex ; Chagford, Devon ; Pass of Leny, Perthshire ; Black
Forest, Baden.

Dimensions. Greatest length 410 fx, more frequently 320 to
350 fx. Corona 38 to 41 /x. Kami about 15 fx. Spurs 6 to 9 /x.

Habrotrocha spicula sp. nov. (PI. 9, fig. 1).

Specific Characters. A single, short, blunt spine, sub-erect
upon dorsal median line of pre-anal segment. Corona small,
13-18 [x wide; pedicels adnate; upper lip high, rounded, un-
divided. Rami with four teeth each. Spurs, short cones, widely
separated.

A rather small species, chiefly noteworthy for the solitary
spine and its unusual position. No other Bdelloid yet known
has only a single spine or has spines only upon the pre-anal
segment as in this case. When the animal is in its most
retracted position, as one usually sees it lying inert among moss
debris, the spine stands out distinctly at the hinder end of the
body, and it is also well shown when the animal is feeding and
assumes the squatting position natural to many species. It is
easily overlooked when the animal is crawling about unless a
good side-view is presented. It springs from a thickened base,
and is rather blunt, short and slightly bent.

When seen from the front the very small corona is nearly
circular in outline, the trochal discs being separated by a shallow
furrow and the pedicels adnate. In dorsal view the high
rounded upper lip rises quite to the level of the trochal discs,
and its apex indeed is visible in ventral view. The margins of the
mouth have small angular lateral prominences, which are partly

90 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA.

visible even from the dorsal side and add to the apparent width
of the collar.

When extended the body is moderately stout and the longi-
tudinal skin-folds are well marked. In most cases it is colourless,
but examples of a faintly reddish colour have been seen. The
antenna is short, but rather stout. The rami are small, 14-15 tt
long.

The foot tapers rapidly and is very short. In the feeding
position it is usually hidden beneath the trunk. It seems un-
suited for crawling on a smooth surface such as glass, as the
animals have unusual difficulty in getting foothold. The first
joint has frequently a strong protuberance on its dorsal side.
The spurs are very small cones about 3 /x long separated by an
interspace about 6 /x wide.

The largest examples measured were about 200 jx long when
extended, but others were from 170 to 185 /x. My earliest speci-
mens were found in mosses collected for me on Cader Idris by
Mr. D. J. Scourfield in 1895. Others came from collections on
Mickle Fell and on Snowdon by the same friend. In 1898
I found it in moss from the top of Ben Ledi, in 1907 from the
top of Ben Vrackie, both in Perthshire ; and in 1906 from tree-
moss in the woods above Triberg in the Black Forest, Baden. It
has also been found repeatedly by Mr. James Murray in Scotland
and in many foreign habitats.

Distribution : cosmopolitan, mostly at high elevations.
Habitat : ground, rock or tree-mosses.

Habrotrocha ligula sp. nov. (PI. 9, fig. 2).

Specific Characters. Moderately slender. Corona somewhat
wider than collar ; pedicels rather high, semi-adnate ; discs
separated by narrow sulcus. Upper lip rising very slightly and
displaying a small fleshy tooth, which near its apex tapers
suddenly to a point. Rami with four teeth each. Foot three-
jointed ; spurs small, tapering cones with interspace nearly equal
to their length.

D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 91

A species of rather less than medium size which in its extended
position offers no obvious character for its recognition. The
rostrum is short and stout, and the dorsal surface has a distinct
almost ridge-like thickening of the hypodermis, best seen in
lateral view. Its movements are active when crawling about,
and when feeding it sways and bends almost incessantly in all
directions, the body being well extended and the upper foot
joints visible. The trochal discs are rather small and the
greatest width of the corona little exceeds that of the collar. The
pedicels are adnate to nearly half their height and are very
slightly divergent. At the dorsal end of the nexus between
them is a small fleshy ligule or tooth, which for the most part is
nearly cylindrical, but near the tip tapers rather suddenly to a
point. It is so inconspicuous that it can rarely be seen except
in direct dorsal view and when the animal keeps steady for a
brief interval. Even then the exact shape of the ligule is
difficult to determine, but I think that it differs somewhat from
the type of ligule possessed by any of the few Bdelloids in which
this peculiar ornament or organ has been seen. In Habrotrocha
eremita (Bryce), in which it was first noted, it is a simple, short,
peg-like tooth, very slender and tapering gradually, and, to judge
from the figures given by Murray, it appears to be of the same
character in Habrotrocha acornis Murray and Callidina lepida
Murray. In the present species the appearance is rather that
of a fleshy cylindrical pedestal, with a tapering point inset at
the end of the pedestal as if in a socket.

The upper lip rises in a low curve about as high as the base
of the ligule. The rami have four teeth, but one tooth on each
is much less prominent than the others. I have noticed that
the food pellets are rather small. Examples isolated produced
eggs of oval outline, hyaline, smooth-shelled, measuring 70 /x at
the longest by 43 //, at the shortest diameter.

I had this species first in 1894 from a roadside near Deal, and
in the following year from a wall in Bognor ; in both cases from
small button-like tufts of w T all-moss. I did not see it again until

92 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA.

some few weeks ago, when it was brought to me by Mr. G. K.
Dunstall, who had obtained it from moss collected near Leith
Hill, in Surrey. It is probably a more common species than
these three isolated records would indicate. It may be that it
has a partiality for small tufts of moss (which do not invite
examination), or perhaps its restlessness and the absence of any
very obvious peculiarity when marching about has led to its
being overlooked.

In view of Murray's opinion that the presence of a ligule in
Bdelloids is an unsafe specific character, as it often appears in
species where it is not normally present, it must be pointed out
that, while it may be presumed that the ligule in Habrotrocha
ligula is fairly constant, it is by no means impossible that
examples should occur in which it might be absent, and in that
case, if normal specimens were not available for comparison,
identification might well be difficult.

Dimensions. Length about 320 fx. Corona 30 /x. Collar 25 /a.
Ramus 1 7 /x. Spurs 5 ll.

Callidina Bilfingeri sp. nov. (PI. 9, fig. 3).

Specific Characters. Of medium size, and moderately stout,
posterior trunk having a series of knob-like prominences.
Trochal discs well separated, but corona not exceeding collar
width. Upper lip rather high and wide, with shallow central
depression. Rami with two teeth each. Dorsal antenna short,
about half the neck thickness. Foot three- jointed; first joint
laterally swollen, second very short, somewhat distended to form
sucker-like disc. Spurs very minute cones, with wide, slightly
convex interspace.

So far as I am aware, this rather well-marked species, of
moderately stout build and medium size, has been met with only
in ground-mosses. Typical specimens are easily recognised from
the series of knob-like prominences which ornament the sides of
the trunk segments and the dorsal surface of the rump segments.

D. BRYCE ON FIVE NEW SPECIES OF BDELLOID R0TIFER4. 93

The number of these "knobs" appears to be very inconstant,
as in sketches made by Forstmeister Bil finger, James Murray,
and myself it varies from eleven to five ; and I was informed
by the first-named correspondent that he had met with examples
without any knobs at all. In such cases the species can still be
determined with moderate certainty from the peculiar structure
of the second foot joint, and the minuteness and wide separation
of the spurs. When the full number of prominences are present
they are distributed thus : the third segment of the trunk (or
central portion of the body) has one at either side, close to its
anterior boundary ; the same segment and the fourth and the
sixth have each one at either side near their posterior boundaries;
while on the dorsal side of the fifth and sixth segments there are
three more, arranged in a triangle (two in front on the fifth
and one behind on the sixth segment, the latter on the median
line). The fifth segment is moderately swollen laterally. The
lateral knobs on the sixth segment (the anal) are more nearly
constant than the others. Those most frequently absent are
the anterior pair of the third segment.

The first foot joint has distinct lateral swellings, and is per-
haps swollen dorsally as well. The second joint is very short,
and slightly distended with thickened skin, forming a sucker-
like disc from the lower surface of which the three short, broad
toes are protrusible. The flange-like hinder margin of this
foot disc forms the slightly convex interspace between two very
minute spurs.

When creeping about the animal is seen to have a short and
stout rostrum. In the feeding position the body is somewhat
flattened, and the dorsal longitudinal skin-folds are obliterated.
The trochal discs are well separated, but the head is stout and
the corona does not exceed the collar width. The upper lip rises
rather widely and high, and has a shallow central depression.
The rami are 14 to 16 ^t long, and are widest above the middle.
The anterior outer margin of each is distinctly thickened, and
passes gradually into a delicate winglike expansion of the ramus.

94 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA.

As already stated, this species was first discovered by the
late Forstmeister L. Bilfinger in the vicinity of Stuttgart, and
notified to me in 1894. It was afterwards found by Mr. George
Western, probably near London, and in 1904 by James Murray,
near Fort Augustus. In 1906 I met with it in moss gathered
on the bank -of a roadside ditch near Triberg, in the Black
Forest. Quite recently numerous examples have been found in
moss collected by Mr. G. K. Dunstall near Leith Hill, Surrey.

Dimensions. Length about 315 /a. Corona 38 /x. Collar 41 /a.

Spurs 1 to 2 /a (on inner edge).
i

Description of Plates 8 and 9.

Plate 8.

Fig. 1. Habrotrocha munda sp. nov., extended, dorsal view, x 350 ;

la, head and neck, corona displayed, in lateral view,

X 650 ; lb, the same, in ventral view, x 750 ; lc,

mouth, in front view (diagrammatic).

2. Habrotrocha torquata sp. nov. In feeding position, corona

displayed, dorsal view, x 550 ; 2a, spurs, x 1600.

Plate 9.

Fig. 1. Habrotroclut spicula sp. nov. In feeding position, corona
displayed, ventral view, x 600 ; la, retracted position,
X 600 ; 16, foot extended, dorsal view, x 800 ; lc, ramus,
X1600.

,, 2. Habrotrocha ligula sp. nov. In feeding position, corona
displayed, dorsal view, x 480.

,, 3. Callidina Bilfingeri sp. nov. In feeding position, dorsal
view, x 350; 3a, ramus, x 1600.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913.

Joum.QM.C.

Ser. 2.Vol.XH,P1.8.

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Journ. Q.M.C.

Ser2.Vol.Xn,P1.9.

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95

NOTES.

A NEW LOW-POWER CONDENSER

By Edward M. Nelson, F.R.M.S.

{Read November 26th, 1912.)

The condensers which at present are supplied with microscopes
are only suitable for low powers ranging from | inch upwards.
With powers lower than these a difficulty arises, for it is not
possible to fill the field with the image of the source of light
focused upon the object, as it should be. Substage condensers
suitable for low powers are all too short in focus, consequently
the image of the source of light is far too small.

In these circumstances microscopists have been, and are,
accustomed to waive critical illumination and employ the most
uncritical of all illumination, viz. to focus the image of the
source of light upon the front lens of the objective ; this is
nothing more nor less than lantern illumination, which gives
a critical image of a diaphragm limiting the field, but of nothing
else ; all delicate lines and structures are coated with black
diffraction borders.

The obstacle in the way of using a long-focus condenser is that
there is not sufficient room to focus it.

Powell's No. 1 stand has a good deal of room, but not enough,
and other microscopes are simply nowhere. Now the way this
difficulty may be surmounted is to construct the condenser upon
the telephoto principle. This has now been done, and Messrs.
Baker will show you this evening a substage condenser they have
made from my design which has 4 inches of focal length and
requires only 1 inch of working distance. With this condenser
the image of the fiat of the flame bears the same relation to a
4-inch objective with the large field of a P. & L. No. 1 A eye-
piece, as the image with one of the ordinary universal condensers,
with the top off, does to a | inch ; and this is precisely what
was wanted.

Now let us understand exactly what this means. A 4-inch
objective has a focal length of 2| inches; with a No. 1 A
eyepiece the size of the object on the stage that is embraced

96 E. M. NELSON ON MICROSCOPE CONSTRUCTION

in a field of view is $ inch, therefore it is necessary for the
condenser to focus upon the stage an image of the flat of the
flame $ of an inch wide.

The condenser has a low aperture of N.A. 0*14, but large enough
for the objectives for which it is intended to be used.

NAVICULA RHOMBOIDES AND ALLIED FORMS.*

(Addendum.)

By Edward M. Nelson, F.R.M.S.
{Bead November 2M7i, 1912.)

With reference to the question, " What was the Amician Test?"
quite accidentally I recently came across a notice to the effect
that the test used by the Jurors at the International Exhibition
(London, 1862) was the Navicula ?'homboides under the name of
JV. affinis. This of course clears up all the difficulty. This
N. rhomboides would have been of the kind termed the
" English " rhomboides in my paper, and would have had 72 to
73 striae in 0*001 inch.

ON MICROSCOPE CONSTRUCTION AND THE SIDE
SCREW FINE ADJUSTMENT.

By Edward M. Nelson, F.R.M.S.

(Bead November 26th, 1912.)

There is one point which has been overlooked with respect to
the evolution of the microscope. It is thought that the modern
plan of placing the coarse adjustment slide and the body upon the
fine adjustment was the invention of Zentmayer (1876), and that
it first appeared in this country in the Ross-Zen t may er model.
This however is not the case, for Powell in 1841 invented this
plan, as well as that of the side pinion fine adjustment, now so
much in vogue.

In the frontispiece of Cooper's Microscopiccd Joumcd an illus-
tration of this model will be found, f Some years ago Mr. T.

* Journal Q.M.C., Ser. 2. vol. ii. p. 93.

f This was the first microscope Powell introduced after Lealand had
joined the firm (vide Journal B.M.S., 1900, p. 287, fig. 78).

AND THE SIDE SCREW FINE ADJUSTMENT. 97

Powell kindly showed me one of these microscopes, but it had
escaped my memory. The coarse adjustment was by rack and
pinion ; this was not attached to the limb by a slide, but by a
kind of cradle. This cradle was pressed down by a spring on
to a horizontal cone, which was moved by a horizontal fine-
adjustment screw, which had a milled head on each side of the
limb.

The importance of this model should be recognised by every one
who uses a microscope, for not only was it the first microscope
to have a side screw, but also it was the first instrument in
which we find the limb attached to the foot on two upright
pillars. This double support to the joint (now almost universally
used) was the invention of George Jackson (President R.M.S.
1852-3). Before this all microscopes that were capable of being
inclined were attached to the foot by a single upright post and a
compass joint.* Powell attached the two pillars to a flat tripod
base by a swivel so that the base could be placed in such a
position as to give the greatest amount of stability however
much the body might be inclined (some makers in copying this
arrangement graduated this arc of rotation !).

Ross copied this kind of joint in the model he brought out in
1843, but substituted two parallel flat plates for the two pillars ;
but Messrs. Smith and Beck adopted the two-pillar form in their
1846 model.

This microscope of Powell's had a Turrell stage, a micrometer
stage, an achromatic condenser, Nicol polarising and analysing
prisms ; so it was in its day an instrument of a very advanced
type. In 1843 Powell & Lealand discarded the two pillars for
the gipsy tripod, which is the best form of foot ever designed.f

Coming now to modern times, horizontal fine adjustments may
be placed in two groups, viz. (a) those with continuous motion
and (b) those without. The drawback which those of the first
kind possess is that the user does not know whether he is
focusing up or down ; and the drawback which all the second
kind, excepting the Berger, have is that of damage and injury to
the delicate moving parts when they butt up against a stop.
The Berger avoids all risk of damage from this source by causing

* Some ancient non-achromatic microscopes had ball and socket joints,
but those early forms are not now under discussion,
t For fig. see Journal R.M.S., 1900, p. 289, fig. 79
Journ. Q. M. C, Series II. No. 72 7

98

E. M. NELSON ON MICROSCOPE CONSTRUCTION.

an idle nut to butt against a stop ; if this nut receives damage or-
strain to its thread it is of no importance. The first kind adopt
a continuous motion in order to secure immunity from this
danger, and put up with the great disadvantage of having a fine
adjustment which does not follow the direction of the movement
of the milled head.

The following simple device has been designed to effectually
prevent any damage taking place. To the right hand side of the
limb, where the micrometer drum-head is placed, a short piece of
tube, threaded on the outside, is fixed, and through it the fine
adjustment pinion passes just like the cannon pinion in a clock.

Fig. 1.

Fig. 2.

An idle nut works on this screw in a slot inside the micrometer
drum. It is then arranged that this nut will permit ten rotations
of the fine-adjustment pinion to be made, and then stop further
motion by butting either against the side of the limb or against
the end of the inside of the micrometer drum. Figs. 1 and 2 will
make this simple device clear without further explanation.

NOTE ON PLEUROSIGMA ANGULATUM.

By Edward M. Nelson, F.R.M.S.

{Read January 28th, 1913.)

About the end of the eighties I took a photomicrograph of a
specimen of Pleurosigma angulation, which had been broken in
a very remarkable manner so that it was possible to demon-

E. M. NELSON ON V LEU RO SIGMA AStiULATUM. 99

strate the existence of two membranes. At one part the upper
membrane had been torn away leaving the lower membrane,
at another the lower membrane had gone while the upper was
left, the rest of the valve having both membranes in position.
These three photomicrographs of the upper, lower and both
membranes were exhibited to the Club. No other specimen I
have seen has been so fortunately fractured as to demonstrate
both membranes so clearly as this one.

The network in one membrane differs slightly from that of
the other, so that after a little practice one is able to state
whether the membrane under observation is an upper or lower
membrane. The upper membrane in P. strigosum resembles
the diamond panes of a leaded light, while the lower is like
wire netting, fig. 3. In P. balticum and allied forms the upper
memb^ine has slit-like apertures in longitudinal rows, while

III

O-go

Fig. 3. Fig. 4.

the lower membrane has circular apertures, fig. 4, where the
circular apertures in the lower membrane are seen through
the intercostal silex of the upper membrane and in a line with
the bars between the slits.

Now at that time it was thought, and probably it is still
the received opinion, that the lower membrane " eye-spotted "
the upper membrane ; by which is meant that the apertures
in the lower membrane are directly below those in the upper
membrane much in the same way as in Coscinodiscus the eye-
spot is directly below the perforated cap at the top of the cell.

Recently, however, study on P. angidatum with a Leitz apo-
chromat, y 1 ^ inch of 1*40 N.A., has caused me to change my
opinion, for the apertures in the lower membrane can be un-
mistakably seen below the intercostals of the upper membrane,
and this is true not only of P. angidatum, but also of all allied
forms that have been examined.

No mention has been made of Mr. T. F. Smith's observation.

100 E. M. NELSON ON PLEUROSIGMA ANGULATUM.

on the structure of the genus Pleurosigma, because this note,
not being an exposition of the structure of this genus, deals
merely with the single fact of my altered opinion with regard
to the apertures in the lower membrane not " eye-spotting "
those in the upper.

The genus Pleurosigma has been seventy years before the
microscopical world, not laid aside, but worked at continuously
by the most skilful microscopists, yet all the problems con-
nected with their structure have not been solved. It is only
by recording from time to time a little bit here and a little
bit there, and by putting these little bits together, that complete
and accurate knowledge of this difficult subject will be attained.

ACTINOCYCLUS RALFSII AND A COLOURED COMA.

By E. M. Nelson, F.R.M.S.
{Read January 28th, 1913.)

The following account of a microscopical phenomenon, never
previously observed, may be of interest.

When working on a mixed diatom gathering, dry and un-
covered, with a Powell & Lealand | inch and a lieberkuhn, there
appeared round an Actinocyclus Ralfsii a wide border of brilliant
orange, green and blue light. The inside of the valve was
uppermost and the bottom of the cup was in focus, so that the
surrounding mist was caused by the out-of -focus edge, which, of
course, was at a higher level. Any one seeing this coloured mist
would have exclaimed what a badly corrected objective ! but if
they had looked at the other diatoms in the field, they would
have seen that the out-of -focus coma was white ! The colour,
then, must be a function of the Actinocyclus. Another objective
with a lieberkuhn, viz. a Powell & Lealand T 4 ^ inch, was tried on
the same diatom ; the border was now red, the green and blue
having gone ! A third objective, viz. a Wenham | inch with
lieberkuhn (really a T 4 <y inch), and the image seen had no colour !

Here, then, we have an example of an object affecting different
objectives differently. Would some of our " brass and glass "
experts kindly take this matter up ?

Joara. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913.

101

NOTICES OF BOOKS.

Problems of Life and Reproduction. By Marcus Hartog,
M.A., D.Sc., F.L.S. 8 x 5J in. ; xx -f 362 pages ; one
plate, 41 figures in the text, and three diagrams. London :
John Murray, 1912. Price 7s. 6d. net.

In taking up this book one cannot avoid a feeling of regret
that the author was unable to carry out his original intention of
writing a general treatise on Reproduction suited to the layman
interested in biological questions. By his researches the author
would have been well fitted for such a task. As it is, the book
consists of a series of papers on debatable subjects in Biology
gathered from various scientific journals and reviews, and ranging
in date from 1892 to 1910. They have been revised in part in
the light of more recent research, and brought up to date.

There is much to interest the microscopist, and to one who is
not already acquainted with them in their original form they may
be recommended. The earlier papers deal with the problems
of reproduction as presented in the Protista conjugation and
rejuvenescence and the beginnings of sexual reproduction or
syngamy. The paper on Fertilisation contains a large number
of interesting facts gathered together ; here the author puts
forward the idea that it is the linin and not the chromatin
(which only serves a purely mechanical function) which is the
real transmitter of inherited properties. This idea is more
fully developed in Chapter 1Y. on " Mitokinetism " a new
force which the author brings to our aid in explaining the
mechanics of the mitotic process of nuclear division. Other
chapters deal with heredity and the inheritance of acquired
characters and Mechanism and Life.

There are a number of illustrations and a coloured plate; a
full index is provided.

102 NOTICES OF BOOKS.

The Beginner's Guide to the Microscope, with a section on
mounting slides. By Charles E. Heath, F.R.M.S. 1\ x
5 in. 119 pages, 45 figures in text. London: Percival
Marshall & Co., 1912. Price Is. net.

In this elementary guide to the study of Microscopy the author-
has treated the subject from a practical point of view, leaving
theoretical matters to the larger books on the subject. With this
little book at hand the beginner cannot fail to gain a useful
knowledge of the instrument, its care and its application. The
methods of illumination, including the dark-ground method, are
fully dealt with. As the author says, the book is intended " to
enable an ordinary man in an ordinary way to interest himself
and his friends by giving sufficient instruction to make him capable
of seeing and showing some of the hidden wonders " revealed by
the microscope.

103

PROCEEDINGS \fy

OF THE

QUEKETT MICROSCOPICAL CLUB.

At the meeting of the Club held on October 22nd, 1912, the
President, Prof. A. Dendy, D.Sc., F.R.S., in the chair, the
minutes of the meeting held on June 25th, 1912, were read and
confirmed.

Messrs. William Elliott and Leabury Edwardes were balloted
for and duly elected members of the Club.

Seventy-three members and live visitors were present.
Thirteen proposals for membership were read by the Hon.
Secretary.

The list of donations to the Club was read and the thanks of
the members were voted to the donors.

A letter addressed to the President by Mr. Charles Peveril
was read, intimating that the late Mr. J. M. Allen, F.R.M.S.,
had bequeathed to the Club his microscopes and apparatus
belonging thereto. This legacy was accepted by the Committee ;
it consists of two microscopes and some small accessories.

The Librarian announced that he had received a copy of
L. L. Clark's " Objects for the Microscope " to replace a copy
missing from the library, also that Prof. Minchin's " Intro-
duction to the Study of the Protozoa " had been presented by
the author.

A communication from Mr. J. Rheinberg, F.R.M.S., " On
Resolutions Obtained with Dark-ground Illumination and their
Relation to the Abbe Theory," in the absence of the author, was
taken as read.

A very interesting paper, " The Foraminifera in their Role
as World-Builders," by Messrs. Earland and Heron- Allen, was
read by Mr. Earland, and illustrated by a large number of
.pictures of the various forms described, which were shown upon

104 PROCEEDINGS OF THE

a screen by Mr. Ogilvy by means of the Epidiascope, and by
specimens of the deposits placed upon the table.

The President said it was hardly necessary to ask them to-
give a hearty vote of thanks to Mr. Earland for reading them
such an interesting paper. A vote of thanks was carried by
acclamation.

Through the kindness of Messrs. Leitz's London representative,
Mr. Ogilvy, the lecture was very efficiently illustrated by the
use of the Leitz universal projection apparatus, which projected
on the screen ordinary lantern -slides, plates and illustrations
from books, etc., single photographs, microscopic sections at
varying magnifications, rock hand-specimens and fossils. The
capabilities of the apparatus, which employs an automatic L-arc,.
taking 30 amp. at about 60 volts, were further demonstrated by
Mr. Ogilvy and his assistants after the meeting. The approxi-
mate candle-power produced is about 10,000. Micro-projection
may be accomplished in the usual horizontal position, and, for
hanging drop slides or other living preparations, a vertical
position is also possible. Besides the projection of lantern-slides
of any size up to 12 cm. square (4|in.), for which a novel and
exceedingly efficient holder is provided, it is also possible to
project larger transparencies up to 20 cm. square (8 in.), or such
preparations as brain sections, etc.

The President said they were all very much indebted to Mr.
Ogilvy for what he had shown them ; he had himself been
greatly interested to see how perfectly the Epidiascope was
adapted for showing drawings, lantern-slides and microscopic
specimens on the screen in a manner which he had not previously
been aware of.

The Hon. Secretary regretted to have to announce the recent
death of Dr. M. C. Cooke, M.A., LL.D., A.L.S., one of t he-
original founders of the Club, and President 1882-3.

At the meeting of the Club held on November 26th, 1912, the
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the
minutes of the meeting held on October 22nd were read and
confirmed.

Messrs. E. Pitt, G. C. Bellamy, T. Tonkin, H. Pulford,.
E. H. Bassett, L. C. Hayward, William Hill, D. A. Mardon r

QUEKETT MICROSCOPICAL CLUB. 105

P. E. Dollin, F. Whitteron, J. M. Coon, E. W. H. Row and
W. Hardinan were balloted for and duly elected members of
the Club.

The list of donations to the Club was read, and the thanks of
the members were voted to the donors.

The President said that members would be very glad to hear
that the announcement made at their last meeting, of Dr. Cooke's
death, was incorrect. They had it apparently on the best
authority, and the scientific Press generally had been similarly
misinformed. lie was sure that all members would hope that
Dr. Cooke would long remain a member of the Club.

The President asked members to extend a hearty welcome to
a visitor, Dr. E. P. Hodges. Dr. Hodges was State Medical
Supervisor for Indiana, U.S.A., had been for many years a
Fellow of the Royal Microscopical Society, and took the greatest
interest in microscopy generally.

Mr. C. Lees dirties, for Messrs. Baker, exhibited a new
one-sixteenth oil-immersion objective of N.A. 1*32. It was
made of a stable glass one that would stand any climate. Its
qualities were appreciated by members, who admired the
excellent definition it gave (with a x 7 ocular) on a fine pre-
paration of Trypanosoma gambiense.

The President made some remarks relating to a new species of
Holothurian. He said he had no formal paper to read, but the
subject had been before the Club a few months ago {Journ.
Q.M.C., Ser. 2, Vol. XI. p. 536), when an Australian visitor,
Mr. F. Whitteron, of Geelong, had brought for distribution a
number of specimens of a species of Holothurian which had an
interesting history. They had been collected in Corio Bay, Port
Phillip. Continental experts had identified the species as Trocho-
dota dunedinensis (Parker). That identification, however, proved
to be incorrect, and, as specimens had been distributed at their
June meeting, he thought it proper to bring the matter before
the notice of the Club. On examining the material he had then
taken, he found that all the calcareous wheels had been dis-
solved, possibly by the medium in which they were preserved
being, or becoming, slightly acid. Fortunately, this failure was
not of importance, as, in a reprint he had received from the
Proceedings of the Royal Society of Victoria, Mr. E. C. Joshua,
of Melbourne, discussed the species found at Geelong, and

106 PROCEEDINGS OF THE

definitely showed that it was not identical with the New Zealand
form. He calls the Geelong species Taeniogyrus Allani. The
President referred to the varying nomenclature of these species.
He considered all the forms closely related, and preferred the
generic name Chiridota, applied by Parker to the New Zealand
form. The differences between the New Zealand and Geelong
species were then considered. The structure of the wheel spicule
had been worked out by Mr. Joshua, and was described in his
paper. The President had worked out the N.Z. form some years
ago, and described and sketched on the blackboard the various
stages observed. The spicule has a broad margin, corresponding
to the rim of the wheel. Then there are six spokes radiating
from the centre, and in some species there is a small hole in the
middle. Specimens of C. dunedinensis exhibit a uniform minute
toothing all round the margin, which is inturned. The other
side of the wheel has a different appearance. The six spokes
show as before ; but the toothed edge is not seen at the top
focus. Further, fresh detail is exhibited in the form of a
six-rayed cross, which stands above the level of the spokes. A
diagram of a vertical section was given. The President said it
was a very curious and wonderful structure, and the development
was of extreme interest. Commencing with the six-rayed cross,
a thickening appears at the end of each ray, and on one surface
only. This was the earliest stage observed. As the thickenings
grow, they exert pressure on each other, and presently each
spoke bifurcates at the extremity. The bifurcated ends begin
to grow outward, and presently meet, and, fusing, form the rim
of the wheel. The rim turns in, and is denticulated all round
the margin. The spicule is, of course, useful as a skeletal
structure ; but it is not at all apparent why such a remarkable
and elaborate form should be required. The chief differences in
C Allani, as compared with C. dunedinensis, are : The margin,
instead of rounding off, remains hexagonal. The face showing
the six-rayed cross is much the same, excepting that it also is
hexagonal ; but the toothed rim is not uniform, but follows
a curve with little bays opposite the angles of the hexagon, and
the toothing is pronounced in parts, but is absent from the bays
or notches. It is very difficult to account in any way for such
minute differences as those noted. The new form, which he
would prefer to call Chiridota Allani, was first found by Mr.

QUEKETT MICROSCOPICAL CLUB. 107

J. M. Allan, near Geelong, and subsequently by Mr. E. C.
Joshua.

Replying to a question, the President said that formalin was
very unsafe to use in such cases, as it frequently becomes acid
after a short time.

Mr. J. Burton said he took some of the material brought by
Mr. Whitteron, and, after some trouble, had found some
wheels in the skin. They looked as though acid had been
previously applied. The wheels showed a tendency to break
down into anchors, reminding one of the well-known Synapta
spicules. The anchor form, as the President had said, was an
early stage in the development of the wheel. The wheels, under
a, binocular, proved to be basin-shaped. There was a second
kind of spicule, something like a drawer- handle in shape, and a
third shape, found only in the tentacles, where it was very
numerous, constituting, perhaps, 50 per cent, of their bulk.

The thanks of the meeting were unanimously voted to the
President for his communication.

Several notes from Mr. E. M. Nelson were read to the meeting
by the Hon. Secretary, as under :

1. "On Microscopic Construction and the Side-Screw Fine
Adjustment," in which he traced the history of this form from
1841 to the present time, with some suggestions of his own for
further improvement.

2. On the Navicula used as a test by the Jurors of the 1862
Exhibition, which he thought was the " English " rhomboides
under the name of Xavicula affinis.

3. " On a New Low-power Condenser : ' for use with objectives
as low as 4 in., the ordinary condenser not filling the field with
light when low powers were used.

The way this difficulty may be surmounted is to construct
the condenser upon the telephoto principle. This has now been
done, and Messrs. Baker exhibited to the meeting a substage
condenser, made from Mr. Nelson's design, which has 4 in. of
focal length, and requires only 1 in. of working distance. With
this condenser the image of the flat of the flame bears the same
relation to a 4-in. objective with the large field of a P. and L.
No. 1, A eyepiece, as the image with one of the ordinary uni-
versal condensers with the top off does to a tw r o-thirds ; and
this is precisely what was wanted.

108 PROCEEDINGS OF THE

The thanks of the Club were voted to Mr. Nelson for his
communications.

At the meeting of the Club held on January 28th the
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the
minutes of the meeting held on November 26th, 1912, were
read and confirmed.

Messrs. Hilary Mavor, Robert Spry, E. J. Sheppard, F.R.M.S.,.
A. C. Coles, M.D., D.Sc., A. M. Allison and H. W. Freeland
were balloted for and duly elected members of the Club.

The list of donations to the Club was read and the thanks
of the members voted to the donors.

Mr. Watson Baker, for Messrs. Watson & Sons, Ltd., ex-
hibited and described a new model microscope which had a
specially long horizontal travel, If in., to the mechanical stage,
both movements working on the same axis. The fine adjustment
is a vertical lever actuated by the now customary side-screw,
and permitting the worker to always know whether the body
is ascending or descending. It has a specially long range of coarse
adjustment. The most important novelty on the stand was a
new objective changer, made on the principle of a 3-jaw chuck ;
less than a quarter-turn of a collar is all that is necessary to
engage or release an objective, and it does not increase the tube
length. An auxiliary stage was also shown. This, fitted to the
usual stage, will give nearly four inches of horizontal travel,
and should be found very useful in working with large pre-
parations.

Mr. A. A. C. Eliot Merlin, F.R.M.S., sent a photomicrograph
taken at x 320 of Coscinodiscus heliozoides, showing extended
" pseudopodia," from a preparation by Mr. J. D. Siddall.

The fine radiating " pseudopodia " can be well seen when the
print is examined in a good light with a Verant or other suitable
hand magnifier. The photograph gives the impression that the
radiating filaments are real appendages of the organism, and
the general appearance of these reminds one strongly of the
pseudopodia of Discorbina globidaris as figured in Carpenter
(1901 edition), page 798.

The photograph as a whole strikes one as more curious than
beautiful. It will, however, be noticed with a lens that several
of the radiating filaments are very fine and in exact focus.

QUEKETT MICROSCOPICAL CLUB. 109

The best focal plane for the " pseudopodia " does not coincide
with that for the diatom itself, and this, together with the
prolonged exposure necessary to bring out the faintly illuminated
filaments, causes the valve to be much over-exposed, making
the diatom appear as a mare blurred, globular white patch in
the print.

The President gave a resume of a communication of some
length by Mr. W. M. Bale, F.H.M.S., of Victoria, Australia,
entitled " Notes on Some of the Discoid Diatoms." This paper
was a survey of some of the principal characters which have
been utilised in the discrimination of species in three or four
of the best-known genera of discoid diatoms. Some of the
conclusions arrived at as to the inadequacy of many of these
distinctions have been reached by previous observers, more
especially in the genus Coscinodiscus ; but it was thought that
in such cases the special instances now brought forward might
be serviceable in reinforcing those conclusions. In other cases,
particularly in the genus Actinoptychus, the author's observa-
tions tended to prove that characters accepted as specific even
by recent authors were demonstrably unreliable. The genera
dealt with included Coscinodiscus, Actinocyclus, Asteromphalus
and Actinoptychus.

The thanks of the meeting were unanimously voted to the
President for communicating this important paper.

A paper on " British Freshwater Bhabdocoelida (Planarians),
a Group of Turbellaria," by H. Whitehead, B.Sc, in the absence
of the author was read by Mr. J. Wilson.

After some discussion, in which Messrs. Scourfield and Ham-
mond took part, the President said that the Bhabdocoelids were
very low down in the scale, some of them ranking among the
lowest of multicellular organisms. Most of his own work in
Australasia had been done on land forms, but there were, pos-
sibly, water forms as well. There were in Australia an enormous
number of land Planarians which lived under stones, rocks, logs,
etc., and only came out at night. Some were very large, reach-
ing a length of one foot. They are locally incorrectly termed
" land-leeches." Many are brightly coloured in stripes, spots,
and patches of brilliant blue, red, yellow, orange, and sometimes
iridescent. These colourations were very useful in assisting
naturalists to identify species. He had described some forty new

110 PROCEEDINGS OF THE

species from Australia and New Zealand, and was very glad to
see that the study of the group was being taken up in this-
country.

The Hon. Secretary read a " Note on Pleurosigma angalaturu"
by Mr. E. M. Nelson, F.R.M.S., also a note on a coloured coma
observed in examining A. Ralfsii, by the same author.

Mr. C. F. Rousselet, F.R.M.S., read a paper on "The Rotifera
of Devils Lake, and description of a new Brachionus."

At the meeting of the Club held on February 25th, the Presi-
dent, Prof. A. Dend} r , D.Sc, F.R.S., in the chair, the minuter
of the meeting held on January 28th were read and confirmed.
There were present ninety -three members and fourteen visitors.

Messrs. H. T. Laurence, F. W. Mills, J. W. Durrad, W. Oatley,
E. A. Anstey, C. D. Hutchin, A. Booker, F. W. Parrott, J. J.
Armitage, N. Burns, J. Snell, A. 0. Trotman, R. A. Taylor,
J. Bancroft, J. E. Barnard, R. Hall, V. Tyas and Dr. J. C.
Kaufmann were balloted for and duly elected members of the
Club.

The list of donations to the Club was read and the thanks of
the members voted to the donors.

The President having appointed Messrs. Fuller and Watson -
Baker, jun., as Scrutineers, the ballot for Officers and Council
was proceeded with.

The Hon. Secretary (Mr. \V. B. Stokes) read the Committee's
forty-seventh Annual Report. It was considered that the past
year was one of marked progress. Forty new members had been
elected; five members had died and fifteen had resigned during
the past year. The total membership on December 31st, 1912,
was 406.

The Hon. Treasurer (Mr. F. J. Perks) presented the Annual
Statement of Accounts and the Balance-sheet for 1912, which
had been duly audited and found correct.

The Report and Balance-sheet were received and adopted, on
the motion of Mr. Morland, seconded by Mr. Gaff.

The President, having asked Prof. E. A. Minchin to take the
chair, delivered his Annual Address, taking as his subject " By-
products of Organic Evolution."

Prof. Minchin said he was sure all present would agree that

QUEKETT MICROSCOPICAL CLUB. Ill

they had listened to a very fascinating address from one who
was the foremost living authority in Europe on sponge spicules.
The Club was very fortunate in having the subject dealt with by
him. The objects were quite well known to all microscopists, and
he believed he was right in saying that all the different forms of
spicules described could be obtained from sponges found on our
own coasts. He had great pleasure in moving a hearty vote of
thanks to their President for his address, and in asking him to
allow it to be published in the Journal.

The motion having been put to the meeting, was carried by
acclamation.

The President, in acceding to this request, thanked the mem-
bers for the way they had received the address, but said he had
thought himself that Prof. Minchin was the greatest authority
they had on these microscopic objects.

A vote of thanks to the Auditors and Scrutineers, having been
moved by Mr. W. R. Traviss and seconded by Mr. A. M. Jones,
was put to the meeting and carried unanimously.

Mr. Bremner then moved that their best thanks be given
to the officers of the Club for their services during the year.
They had given them a very valuable amount of time with a
most excellent result. Mr. Stokes had referred to the work
done by their Librarian, which must have occupied hundreds
of hours, and as for Mr. Stokes himself his unfailing courtesy
and his capacity for hard work were deserving of their highest
appreciation.

Mr. A. D. Michael said he always felt very strongly that
the great success which attended the scientific societies of London
was mainly due to the work done by their officers. He had
much pleasure in seconding the vote of thanks to those who had
so ably conducted the business of the Club during the year.

Mr. W. B. Stokes said that as this was the last occasion on
which he would be able to speak as an officer of the Club he
would reply for his colleagues ; he thanked the members for
the vote they had just carried. He felt he was leaving the
Secretaryship in better hands than his own ; but was very glad
that he was leaving it not when the Club was at the bottom
of a curve of prosperity, but very nearly at the top. He thanked
the officers for the ready assistance which they had always given
him, and which had rendered his duty a pleasant one, and he

112 PROCEEDINGS OF THE QUEKETT MICROSCOPICAL CLUB.

desired also to thank the members for the kind way in which
they had supported him during his term of office as their
Secretary.

The President announced the result of the ballot for Officers
and Committee to be as follows :

President

Vice-Presidents

Treasurer .
Secretary

Assistant Secretary
Foreign Secretary
Reporter ....
Librarian .
Curator ....
Editor ....

Vice four senior
Members retired.

Vice James Burton
{apptd. Secretary.)

Prof. Arthur Dendy, D.Sc, F.R.S.,
F.L.S.

C. F. Rousselet, F.R.M.S.

E. J. Spitta, L.R.C.P., M.R.C.S.,F.R.A.S.

D. J. Scourfield, F.Z.S., F.R.M.S.
.Prof. E. A. Minchin, M.A., F.R.S.

Frederick J. Perks.
James Burton.
J. H. Pledge, F.R.M.S/
C. F. Rousselet, F.R.M.S.
R. T. Lewis, F.R.M.S.
S. C. Akehurst.
C. J. Sidwell, F.R.M.S.
A. W. Sheppard, F.Z.S., F.R.M.S.
R. Paulson, F.R.M.S.
J. Grundy.

M. Blood, F.C.S., F.R.M.S.
.0. D. Soar, F.L.S., F.R.M.S.
R. Inwards, F.R.A.S.

11

o

FORTY-SEVENTH ANNUAL REPORT,

Reviewing the work of the Club during the year 1912 shows
that it has been a period in which its high value to the user
of the microscope has been again demonstrated. Not only has
the Club maintained the interest of its meetings, but it has
exhibited a revival of interest in matters connected with the
instrument itself. There has been a very good attendance at
conversational meetings, and the favour shown to the excursions
during a season having a record rainfall is well worthy of note.
The number of new members added during the twelve months
is forty, 50 per cent, advance on that of 1911, and this number
would have been even greater if an ordinary meeting in Decem-
ber had been possible. The Club has lost five members by
death, and resignations have accounted for fifteen ; this leaves
a net gain of twenty members. The total membership on
December 31st was 406.

The following communications have been made during the
year :

Jan. James Burton. Notes on Algae collected in 1911.

Feb. Prof. E. A. Minchin, F..R.S. Some Speculations with

regard to the Simplest Forms of Living Beings and
the Origin of Life.
March. H. Sidebottom. Lagenae of the South-west Pacific.
C. F. Rousselet, F.R.M.S. On New Species of Rotifera.

,, D. Bryce. On New Species of Callidina.

A. E. Conrady, F.R.A.S. On Resolving Powers ob-

tainable with Dark-Ground Illumination.
A. A. C. Eliot Merlin, F.R.M.S. On the Capped

Secondaries of Navicula Smithii.
April. John Stevens, F.R.M.S. On Notommata glgantea
(Glascott).
Duncan J. Reid. Illumination in Critical Work.

May. E. M. Nelson, F.R.M.S. On the sculled fseudopodia
of certain Diatoms.
Journ. Q. M. C, Series II. No. 72. 8

114 FORTY-SEVENTH ANNUAL REPORT.

May. R. T. Lewis, F.R.M.S. Notes on Solpuga.

,, A. E. Oonrady, F.R.A.S. Some Experiments on Alter-

native Microscopical Theories.
June. W. B. Stokes. Resolutions obtained with Dark-
Ground Illumination and their Relation to the
Spectrum Theory.
R. W. H. Row. On a Saw-fly.

Oct. Julius Rheinberg, F.R.M.S. On Resolutions obtained

with Dark-Ground Illumination and their Relation
to the Abbe Theory.
A. Earland, F.R.M.S., and E. Heron-Allen, F.L.S.
Foraminifera as World Builders.
Nov. Prof. Arthur Dendy, F.R.S. On a New Species of

Holothurian.
E. M. Nelson, F.R.M.S. On Microscope Construction.

On Namcula rhomboides.

55

M 55 5? >5

On a New Low-Power Con-

55 55 5) 55

denser.

The following exhibits were made :

Jan. E. M. Nelson, F.R.M.S. Photomicrographs.

,, A. Earland, F.R.M.S. Photomicrographs of Recent

Foraminifera.
W. Watson & Sons, Ltd. Microscope Tray.

,, Charles Baker. Nelson's Dark-Ground Illuminator.

March. T. W. Butcher, F.R.M.S. Photomicrographs of Nam-
cula Smithii.
Charles Baker. Nelson's Oil Immersion Dark-Ground

Illuminator.
,, Charles Baker. Nelson's Improved Chromatic Con-

denser.
Charles Baker. Nelson's Improved Rousselet Com-

pressor.
April. C. D. Soar, F.R.M.S. Drawings of Water-Mites.
A. W. Stokes. Electric Lamps for the Microscope.

C. F. Rousselet, F.R.M.S. Diatoms with "Pseudo-

podia."
Charles Baker. A New l|-in. Objective of N.A, 0'18.

Oct. E. Leitz. The Epidiascope.

FORTY-SEVENTH ANNUAL REPORT. 115

Nov. Charles Baker. A New l/16th-inch Oil Immersion
Objective.
,, Charles Baker. Nelson's New Low-Power Condenser.

Your Committee wish to thank the authors and exhibitors
for these interesting communications and exhibits. It will be
seen that there has been no falling-off in either the quality or
quantity of papers submitted to the Club.

There were eleven excursions during the season, and all were
well attended, except on one occasion when the weather was
very bad ; the record number of fifty-three members met to visit
the Royal Botanic Gardens. The total attendances for all ex-
cursions was 235, which is also a record for any one year, and the
average of 21*4 per excursion has only been exceeded once before.

The collecting, though not including anything new, was always
satisfactory.

The thanks of the Club are due to the Secretary of the Royal
Botanic Gardens and to the Metropolitan Water Board for
permission to visit their enclosures ; also to the Port of London
Authority and Mr. Carlyle, who so kindly entertained the
members at tea after their visit to the Surrey Commercial Docks.
Later in the year a party of members gave an exhibition of
Pond Life at the Dock Club and Institute, on which occasion
Messrs. Soar, Offord and Wilson gave short lectures with lantern
illustrations.

The Hon. Librarian and his assistant have expended a con-
siderable amount of time and labour upon the classification and
arrangement of the Club's books, and great progress has been
made with the preparation of the new catalogue. The amount
allotted to the cost of binding has been exceeded by 5, and
repairs and cases for loose parts have cost about <11. The
question of the elimination of periodicals containing nothing of
particular interest to microscopists is before your Committee ;
the limitation of space for housing the Club's books being a
difficulty that it has to meet. The Library has been used in
1912 as much as in previous years, but the cost of housing
relatively to the use that is made of the books presents quite
a serious problem for consideration by your Committee.

During the year under review the following volumes have been
added :

116 FORTY-SEVENTH ANNUAL REPORT.

LIST OF BOOKS PURCHASED SINCE APRIL 1912.

SlJSSWASSERFAUNA DEUTSCHLANDS :

Part II. Copepoda, Ostracoda, Malacostraca.
,, XIV. Rotatoria and Gastrotricha.

Science of the Sea. Edited by G. H. Fowler. Issued by the
Challenger Society.

Huyghen's Treatise on Light. Translated by Prof. Silvanus P.
Thompson.

Also fifty copies of Henry Sidebottcm's paper, " Lagenae of

the South-West Pacific Ocean," reprinted from the Q. M. C.

Journal, April 1912, Vol. XI. These copies may be purchased
at 2s. Qd. each.

LIST OF BOOKS PRESENTED SINCE APRIL 1912.

Presented by the Author, E. Penard :
Notes sur quelques Sarcodines. Part I.

Presented by ft. T. Lewis :
Objects for the Microscope. 2nd Ed. . . L. Lane Clark.

Presented by Julius Rheinberg :
Spectrum Method of Colour Photography.

Presented by the Author, Prof. E. A. Minchin :
Introduction to Study of Protozoa.

Presented by James Motham :
List of the Fossil Radiolaria from Barbados. A. Earland.

Figured in Ehrenberg's Fortsetzung.
Radiolaria ....... A. Earland.

Reprinted from the Q. M. C. Journal, April 1900.

Presented by Mrs. D. Wesche :

Phylogeny of the Nemocera . . . W. Wesche.

With notes on the leg bristles, hairs and certain mouth glands
of Diptera.

FORTY-SEVENTH ANNUAL REPORT. 117

Presented by the Author, E. Penard :
Notes sur quelques Sarcodines. Part II., 1906.

Presented by the Author, Dr. J. B. De-Toni :

Sylloge Algarum :

Vol. T. Sections I. and II. Chlorophyceae.

,, II. Bacillarieae.

,, III. Fucoideae.

,, IV. Sections I., II., III., IV., Florideae.

,, V. Myxoph}-ceae.

Presented by the Author, C. E. Heath :
Beginners' Guide to the Microscope.

During the year ending December 1912 the Library has
received the following publications :

Quarterly Journal of Microscopical Science.

Victorian Naturalist.

Mikrokosmos.

Royal Microscopical Society.

British Association.

Royal Institution.

Geologists' 1 A ssociation.

Manchester Literary and Philosophical Society.

Hertfordshire Natural History Society.

Bristol Naturalists' Society.

Birmingham Natural History and Philosophical Society.

Botanical Society of Edinburgh.

Glasgow Naturalists Society.

Croydon Natural History Society.

Indian Museum (Calcutta).

Royal Society of New South Wales.

American Microscopical Society.

Sin ithsonian Instit ution.

Academy of Natural Science, Philadelphia.

Missouri Botanic Garden.

Philippine Journal of Science.

Bergen Museum.

Lloyd Library, Cincinnati.

118 FORTY-SEVENTH ANNUAL REPORT.

U.S. National Herbarium.

Royal Society. Series B.

Natural History Society of Glasgoiv.

Zoologisch-botanischen Gesellschaft, Wien.

Redia.

U.S. National Museum.

Nuova Notarisia.

Nyt Magazin.

Birmingham and Midland Institute and Scientific Society.

Liverpool Microscopical Society.

Nova Scotian Institute of Sciences.

Royal Dublin Society.

Canadian Institute.

University of California.

Tijdschrift.

Illinois State Laboratory of Natural History.

Scottish Microscopical Society.

The Club's collection of slides has been increased by 133
preparations, including a further donation of fifty Freshwater
Rhizopods from Dr. Penard. An interesting donation consisted
of several fine injected anatomical preparations mounted by the
late Sir Benjamin W. Richardson over fifty years ago, which are
still in perfect condition. It is proposed to publish in future
issues of the Journal lists of additions to the Cabinet, and these
lists will serve as a supplementary catalogue of slides ; the first
list was published in the November issue. Two microscopes with
several objectives and accessories were bequeathed to the Club
by the late J. Mason Allen, so that the Club is now well
provided with microscopes for exhibiting objects at the meetings.

The thanks of the Club are due as in former years to the
editors of the English Mechanic and Knowledge for publishing
excellent reports of the ordinary meetings. Those in the former
journal are of great use in keeping country members au courant
with the doings of the Club.

Your Committee desires to thank the officers for their services
during the past year, and desires to call attention to the
following resolution which was passed by them at their meeting
on January 28th :

" That the Committee accept with grtat regret the resignation

FORTY-SEVENTH ANNUAL REPORT. 119

of Mr. W. B. Stokes as Secretary of the Club, and in so doing
desire to express their hearty thanks to Mr. Stokes for his
valuable services."

Your Committee sees nothing to prevent the Club maintaining
its traditional usefulness. There is no question as to the need
of such an institution ; but there is need to remind members
of the importance of the Club being all it seems to be to the
new-comer, and not a cause of disappointment. The latter
condition need never obtain if the dual role of the Club be
maintained, presenting an effective means of publicity for the
specialist and a help to the less experienced amateur.

120

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121

ON SOME FORAMINIFERA FROM THE NORTH SEA
DREDGED BY THE FISHERIES CRUISER "HUX-
LEY" (INTERNATIONAL NORTH SEA INVESTIGA-
TIONSENGLAND).

By Edward Heron-Allen, F.L.S., F.G.S., F.R.M.S., and
Arthur Earland, F.R.M.S.

{Head March 25th, 1913.)

Plates 10, 11.

In connexion with our paper on the distribution of Psammo-
sphaera and Saccammina in the Northern Area of the North
Sea,* Mr. J. 0. Borley, M.A., of the Fisheries Department,
Board of Agriculture (England), suggested a continuation of our
investigations into the Southern Area. With some reluctance we
undertook the work, having little expectation of any tangible
results, as Mr. Borley had already, from his personal experience
of dredging in these waters, confirmed the generally held belief
that rhizopodal life was of very sparing occurrence in the area
in question. The shallowness of the sea and the consequently
excessive wave action in this area were thought to be factors
limiting the development of rhizopodal life, as compared with
the conditions in the Scottish North Sea, where the average depth
is greater and the disturbance due to the action of waves and
currents is consequently less.

By the courtesy of the officers of the Board the dredgings
made by the Fisheries Cruiser " Huxley " were placed at our dis-
posal, and, guided by the admirable charts plotted by Mr. Borley
to show the distribution of " silt areas " in the North Sea, six

J

* "On some Foraminifera from the North Sea, etc., dredged by the

Fisheries Cruiser " Goldseeker " (International North Sea Investigations
Scotland). II. On the distribution of Saccammina sphaerica (M. Sars) and
Psa)iimos])haera fusca (Schulze) in the North Sea." Journ. R. Micr. Soc.
1913, pp. K26, pis. i.-iv.

Journ. Q. M. C, Series II. No. 73. 9

122 E. HERON- ALLEN AND A. EARLAND ON SOME FORAMINIFERA

dredgings were selected, three from the most northerly area
dredged by the " Huxley" and three from an area considerably
farther south.

The three Northerly Stations selected lie far to the N.E. of
the Dogger Bank, in the centre of the North Sea, and in what
is, strictly speaking, the Scottish area of that sea. They lie in
the neighbourhood of the Great Fisher Bank, and are contiguous
to the most southerly line of " Goldseeker" Stations (Stns. 41,
41 B , 41 A , 42, etc.) but farther out to sea towards the east. These
three stations are referred to in the following paper as the
Northern or Outer Area.

The three Southern Stations selected lie in the deep trough of
water between the Dogger Bank and the Northumbrian coast,
and are quite close to the shore. They are referred to in the
paper as the Southern or Inner Area.

These dredgings were carefully selected with the view of obtain-
ing the muddiest deposits possible, such conditions being most
favourable for rhizopodal life ; and they probably represent the
richest of the " Huxley " dredgings, all the others which were
cursorily examined consisting of clean siliceous sand with hardly
any trace of microzoa. Such deposits, Mr. Borley assures us, are
typical of the greater part of the Southern North Sea.

Owing to the widely separated stations selected the microfauna
of these six dredgings may probably also be regarded as typical
of the inshore and midsea areas. The comparative richness of
the fauna of the Southern Area, as compared with the Northern,
is undoubtedly due to the proximity of the coastline and the
abundant food supply derived from the coastal deposits.

All the dredgings consisted of loose sands containing a con-
siderable amount of mud ; but whereas the sands from the
Northern Area were easily cleaned (like the majority of the
"Goldseeker" dredgings from adjacent stations), the sands of
the Southern Area proved somewhat refractory. They con-
tained numerous pellets of hardened mud which resisted dis-
integration, and even the action of a strong solution of boiling

FROM THE NORTH SEA. 123

soda did not completely remove the adherent mud from the sand-
grains and foraminifera.

This is a noticeable feature, because as a rule muddy dredgings
are readily broken down if thoroughly dried before the cleaning
process is commenced, and even the most stubborn muds generally
succumb to the action of boiling soda.

We have, however, met with similarly refractory muds at a few
of the " Goldseeker" stations in the Moray Firth, and are unable
to satisfy ourselves as to the cause of this viscosity, which is
quite possibly due to different causes in separate localities.
Among the various explanations which have occurred to us are :

1. The presence of the Hag (Myxine glutinosa). This loath-
some fish is very common at some of the " Goldseeker " stations
where the viscosity has been observed, and as when captured
or touched it exudes an incredible quantity of slime, it is quite
possible that the presence of this fish in any numbers might
locally influence the nature of the sea-bottom. But Mr. Borley
tells us that Myxine is rare in the vicinity of the Stations
sampled, so it may be dismissed from consideration so far as the
" Huxley " material is concerned.

2. Chemical changes in the mud owing to its having passed
through the digestive organs of worms and Echinoderms, many
of which obtain their nutriment by swallowing mud and extract-
ing the organic matter. Thus, in the deep water of some of the
Norwegian fjords, the bottom deposit consists of a very fine
mud full of the tests of rhizopods and swarming with Annelids.
When the mud is dried and broken down again in water, and
the foraminifera have been removed by floating and elutriation,
a mass of fine granular material is left which under the micro-
scope proves to consist of small oval pellets of mud, the excreta
of worms (PL 11, fig. 2).* These pellets resist the action of
soda, making it evident that the mud must have become altered,

* Such deposits are presumably similar to those referred to by Dr. Johan
Hjort under the name of "coprolitic muds." See The Depths of the Ocean,
by Dr. J. Hjort and Sir John Murray (1912), p. 148.

124 E. HERON- ALLEN AND A. EARLAND ON SOME FORAMINIFERA

/

or at any rate that the separate particles must have become
agglutinated during their passage through the alimentary canals
of the worms. Annelid remains are of fairly frequent occurrence
in the "Huxley" dredgings from the Southern Area, but not
noticeably so.

3. It is a matter of common knowledge that fresh mud or
clay, if dried, breaks down readily in water ; but that, if it is
worked or "puddled" before being dried, it becomes plastic, and
then resists disintegration. It is possible that wave or current
action might thus serve to cover the surface of sand-grains and
foraminifera with a coating of mud in a plastic or colloidal
condition, and on the whole we are inclined to favour this
explanation, so far as the viscosity of the " Huxley" deposits is
concerned.

The whole question, however, though interesting from the
point of view of the chemist and physicist, lies rather outside
the province of the zoologist, although it seems evident that the
phenomenon might be of great importance from the geological
point of view, as such viscosity would favour the preservation of
the encrusted microzoa.

A very noticeable feature in the " Huxley " dredgings is the
roundness of the sand-grains as compared with those of "Goldseeker"
dredgings from similar deposits. This is conclusive evidence that
the grains have travelled a great distance, or have been sub-
jected to tidal action within restricted geographical limits for a
prolonged period in comparatively shallow water. The phe-
nomenon has been observed in connexion with the Goodwin
Sands. The scour of the tides and currents round the Dogger
and Great Fisher Banks is doubtless the cause of the rotundity
of the " Huxley " sands, the individual grains of which are often
as smooth and polished as the Aeolian sands of the desert
(PI. 11, fig. 3).*

* Laboratory experiments have proved that a quartz grain -$ in. in
diameter requires an amount of abrasion equal to that acquired in
travelling- a distance of 3,000 miles in water before it becomes rounded to
the form of a miniature pebble. (Daubree, Geologw Experimentale, Paris,

FROM THE NORTH SEA. 125

To return to the microscopical investigation of the " Huxley "
material : as already stated, this was originally undertaken solely
with the view of extending our study of the distribution of two
species, viz. Psammosphaera fusca (Schulze) and Saccammhut
sphaerica (M. Sars), and the results, so far as they affect those
species, have already been published in our paper dealing with
these forms.* But in the course of an examination of the
material we found so many other forms that we determined to
make a systematic list of the species recorded. This list, which
we now publish, contains no less than 133 species or varieties,
many of which have not been recorded previously from the areas
in question.

It must not be concluded, from the occurrence of so extended
a list, that the material was rich in foraminifera. So far from
this being the case, the majority of the dredgings, previous to
manipulation, gave little or no striking indication of organic
remains beyond the presence of a few shell- fragments, spines of
Echinoderms, annelid tubes, and an occasional rhizopod. The
dredgings quite justified in superficial appearance the opinion
which Mr. Borley and other zoologists familiar with the North
Sea had formed, viz. that it was practically devoid of foraminifera.
But careful and repeated elutriations of the dredgings resulted
in the separation of small quantities of light material at each
station, and, as is often the case, these minute samples yielded
a more diverse fauna than .is often found in richer gatherings.
Except in the case of a few dominant species, however, the
number of actual specimens observed was very small. Even in
the case of the dominant species the proportion of individuals
observed to the total bulk of the dredging was too insignificant
to be estimated. The relative abundance of the species in the

1807, p. 47, and Phillips, Q. J. Geol. Soc, vol. xxxvii., p. 21). But the
dynamics of the troubled waters of the North Sea are probably quite
different from the controlled action of a revolving cylinder in a laboratory
experiment !

* Journ. R. Micr. Soc, 1913, p. 25.

126 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA

annexed lists, as indicated by the letters C, R, VR, etc., must
be understood to refer to their abundance as inter-contrasted with
other foraminifera, and not to their frequency in the whole bulk
of the dredging.

A noticeable feature in the dredgings of the Southern or Inner
Area is the relative frequency of specimens of fossil foraminifera.
They are principally small types derived from cretaceous strata
and such as are commonly found in shore sands and shallow-
water dredgings round the southern coasts of England. But a
few larger and well-developed fossil specimens of Nodosaria and
Cristellaria were noted in Hauls 869 and 871, which are not
cretaceous. These are perhaps derived from the Crag, a sub-
marine outcrop of which formation is believed to extend across
the North Sea * ; but they are not all deeply stained with iron,
as is usually the case with the larger foraminifera of the Crag,
and may be derived from the Gault.

Only one fossil was recorded from the Northern Area, viz.
Spirolocidina impressa Terquem. This is no doubt derived from
some submerged Tertiary deposit. It may be noted that Tertiary
foraminifera have been dredged by the " Goldseeker " in the Moray
Firth.

The fossils recorded are :

Spiroloculina impressa Tei quern, Northern Area, one specimen.
Textularia globulosa Ehrenberg, Southern Area, all stations.
Nodosaria pauperata d'Orbigny, Southern Area, two stations.
Nodosaria plebeia Reuss, Southern Area, one station.
Cristellaria costata Fichtel and Moll sp., Southern Area, one

specimen.
Cristellaria rotulata Lamarck sp., Southern Area, one station.
Globigerina aequilateralis Brady, Southern Area, one station.
Globigerina cretacea d'Orbigny, Southern Area, two stations.

* The appearance of many shell fragments dredged from a band of the
sea bed stretching roughly from the Suffolk ccast to the Continent
suggests that they come from the Crag. These, however, are iron-stained
and curiously glazed in appearance in seme, but not in all cases, owing
to attritiop.

FROM THE NORTH SEA.

~>7

127

One of these species, viz. Cristellaria rotulata Lamarck sp., was
also recorded as a recent form.

An examination of the list of species at the different stations
reveals several noticeable features. Taking the three stations in
the Northern Area first, it will be seen that they vary greatly
in richness, Haul 767 yielding only 14 species, as against 26 in
Haul 770 and 54 in Haul 772. Even the richest haul in the
Northern Area contrasts badly with the poorest haul in the
Southern Area, which yielded 72 species, the other Southern
hauls yielding 79 and 94 species respectively.

This discrepancy is largely explained by the abundant records
of the Family Lagenidae in the Southern Area. The figures are
very striking, fossils being disregarded :

Northern Area.

Southern Area

Lagena .

8

30

Nodosaria

3

Lingulina

1

Margin ulina

1

Vaginulina

1

Cristellaria

2

Polymorphina .

2

4

Uvigerina

2

2

Total

12

44

The abundance of Lagenidae in this Area off the Northumber-
land coast has already been noted by Brady.* But in the
" Huxley " dredgings only the genus Lagena is noticeably
abundant, the other genera of the family not being well
represented.

The other families exhibit a similar discrepancy in the lists of
species recorded from the two Areas, but it is not so noticeable
as in the case of the Lagenidae.

* Report British Association, 1862, p. 122; also Trans. Tyneside
Naturalists Field Club, 1863, vol v., part 4, p. 292; Ibid., 1864. vol. vi.,
part 2, p. 194.

128 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA

The dominant forms in the two Areas are as follows * :

Northern.

8. Miliolina seminulum Linne
sp.

21. Reophax sco?yiurus Mont-
fort.

26.

37.

42.
69.
82.
97.

100.

106.
118.

123.

124.
126.

132.

Verneuilina polystropha

Reuss sp.
Bulimina fusiformis W ill .

Polymorphina compressa

d'Orbigny.
Polymorphina sororia

Reuss.

Truncatulina lobatula W.

& J. sp.
Rotalia Beccarii Linne sp.

Nonionina depressula W.

& J. sp.
Polystomella striatopunc-

tata F. & M. sp.

Southern.

Miliolina seminulum Linne sp.
Reophax scorpiurus Montfort.

Haplophragmiiim p>se udosp irale

Will. sp.
Verneuilina polystropha Reuss

sp.
Bidimina fusiformis Will.
Lagena laevigata Reuss sp.
Lagena striata d'Orbigny sp.

Globigerina rubra d'Orbigny.
Truncatulina lobatula W. & J.

sp.
V C at one station only.
Rotalia orbicularis d'Orbigny.
Nonionina depressula W. & J.

sp.
Polystomella striatopunctata F.

& M. sp.

Several of these forms are more abundant in one Area than in
the other, as may be seen by reference to the table.

Some of the discrepancies in the above comparative list can be
explained by what we know of the distribution of the species in
other rhizopodal faunas. Thus (26) Haplophragmiiim pseudo-
spirale Will. sp. (PI. 10, fig. 2-4) appears to be confined to coastal
deposits. It is very common in many muddy shallow-water
dredgings round the W. coast of Ireland and Scotland and in
the Shetlands, but the u Goldseeker " records in the North Sea are

* The numbers refer to the tabular list at the end of the paper.

FROM THE NORTH SEA. 129

very few and entirely confined to coastal gatherings. It does not
occur in any of the midsea " Goldseeker " dredgings from stations
adjacent to the Northern Area of the " Huxley"

Of the other species recorded in the list a few have more than
a passing interest. (1) Nubecularia lucifuya Defrance is a southern
form, not previously recorded on the S. and E. coast of Britain
beyond Bognor, Sussex. A few specimens have been dredged by
the "Goldseeker " in the Moray Firth and Shetland seas, and these
two records, from intermediate localities, are therefore of interest.

The same remarks apply to (9) Massilina secans d'Orbigny sp.
This is the most abundant and typical Miliolid of the shore
sands and shallow water all round the S. and W. coast-line.
There are few records of shore sands on the E. coast, but the
species occurs at Cromer and St. Andrews (Fife) and is abundant
at Scapa in Orkney in shore sand. It is extremely rare in the
" Goldseeker '" North Sea dredgings, but the few specimens found
were from a Station (39 B ) near the " Huxley " Northern Area.
Its absence from the Southern Area is noticeable, and probably
due to the muddiness of the deposit.

(12) Comuspira striolata Brady. The specimen from Haul 767
(Northern Area) is of the very fragile and etiolated type abun-
dant in many of the " Goldseeker " dredgings from the deeper
North Sea.

(13) Comuspira diffusa Heron- Allen and Earland * (P\. 11,
fig. 1). The specimens of this form, which has been recently
described by us, were large and quite typical, but few in number.
The Northern Area is quite close to the " Goldseeker " Stations at
which it is most abundant, but the species is sparingly distributed
round the British coast.

(14) Bathysiphon argenteus, (62) Layena cymbula (PL 10,
figs. 10-12), (84) Layena unyuis, and (117) Discorbina Praeyeri

* " On some Foraminifera from the North Sea, etc., dredged by the
Fisheries Cruiser. " Goldseeker " (International North Sea Investigations
Scotland). III. On Comuspira diffusa, a new type from the North Sea."
Journ. R. Mior. Soc., 1913, pp. 272-6, pi. xii.

130 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA

are new forms discovered first by us in " Goldseeker " dredgings.
They are described and figured in our report on the Foraminifera
of the Clare Island Survey (Proc. Roy. Irish Acad., 1913, vol. xxxi.,
No. 64).

(20) Reophax nodulosa Brady (PI. 10, fig. 1) is extremely
rare as a British species. It has been recorded from the Clyde
Area and Skye by Robertson and from the Estuary of the Dee
by Siddall. The British specimens are very minute, but in the
deep sea it attains a great size, up to 1 in. in length.

(23) Haplophragmium anceps Brady, another deep-water form,
is of rare occurrence in British waters. It has been recorded
from shore sands at Southport (Chaster) and Bognor (Earland),
and we have recently dredged it in the Clare Island Area.

(25) Haplophragmium crassimargo Norman (PL 10, fig. 5-6),
a large and very robust form closely allied to H. canariense
d'Orbigny sp., is the typical Haplophragmium of the deeper parts
of the North Sea, and is abundant in many of the " Goldseeker "
dredgings.

(27) Thurammina papillata Brady. The single specimen re-
corded from Haul 369 in the Southern Area is extremely small,
but quite typical of the spherical type (cf. Brady, Foraminifera
of the u Challenger" 1884, pi. xxxvi., fig. 7). The papillae are
prominent and very numerous. The genus Thurammina is
abundant and very variable in the deep water of the North Sea
to the N.E. of Shetland, but very rare in the central North Sea.

(28) Ammodiscus incertus d'Orbigny. All the specimens are
very minute and of a light-grey colour. The genus is very
sparingly distributed in all the " Goldseeker " dredgings from the
North Sea, and all the specimens are minute. In the Faroe
Channel, however, it attains its full dimensions.

(35) Spiroplecta biformis Parker and Jones sp. (PI. 10,
fig. 9). The single specimen of this rare form, recorded from
Haul 772 in the Northern Area, is noticeable for the rapid
increase in size of the Textularian chambers following the Spiro-
plectine portion of the test.

FROM THE NORTH SEA. 131

(37) Vemeuilina polystropha Reuss sp. All the specimens of
this species, one of the most abundant and typical North Sea
forms, belong to the large coarsely built type, except in Haul 770
Northern Area, where also a few individuals of the minute and
delicate type described and figured by us in the Clare Island
Survey Report were observed.

(38) Clavulina obscura Chaster (PI. 10, figs. 7, 8), occurs in
both Areas, but whereas the Northern Area yielded only a single
specimen, the species attains an extraordinary development both
as regards size and abundance in Haul 871 in the Southern
Area. It is usually a very rare species, though widely distributed
round our coasts in muddy gatherings.

(91) Lingulina carinata d'Orbigny. The single specimen from
Haul 869 Southern Area is of a minute type. Such specimens
occur sparingly in most of the " Goldseeker" dredgings from
muddy areas.

(92) Marginulina glabra d'Orbigny. The single specimen from
Haul 871 is very minute. Rut the species is abundant and
attains a very large size in the deeper waters of the North Sea
to the N.E. of Shetland.

(106) Globigerina rubra d'Orbigny (PI. 10, figs. 13-15). This
species is one of the commonest Globigerinae all over the North
Sea and often forms a large proportion of the finer material
dredged on muddy bottoms.

(110) Discorbina Chasterl Heron-Allen and Earland. Origin-
ally described by the late Dr. Chaster of Southport under the
specific name Discorbina minutissima. This specific name having
been previously used by Seguenza for another form, we have
(in the Report on the Foraminifera of the Clare Island Survey)
renamed the species after its original discoverer. It is of common
occurrence in muddy dredgings from all the shallow coastal
deposits of the North Sea and around the Western shores of
Britain generally.

(112) Discorbina Mediterranensis d'Orbigny sp. and (115) Dis-
corbina Peruviana d'Orbigny sp. are old specips which we propose

132 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA

to revive for sub-types of the " rosacea " group, under a scheme
which is fully explained in our Clare Island Report.

(133) Polystomella crispa Linne sp. The occurrence of only a
single specimen of this species in the Southern Area is very
noticeable, as it might have been expected to occur more plenti-
fully so near the coast. But as regards the single specimen from
the Northern Area, its occurrence there is still more noteworthy,
as the species is extremely rare in the " Goldseeker " dredgings
even in the proximity of the coast and none have been previously
found so far out at sea as this. The specimen is, however,
very water- worn, and may have been current-borne for a great,
distance.

List of " Huxley " Stations from which Material

was Examined.

(

A. Northern or Outer Area lying N.N.E. of the Dogger
Bank.

1. Haul 767, Station xix., 56 53' N., 3 43' E. Dredging made

July 22nd, 1906, in 35 fathoms, to the S.W. of the Great
Fisher Bank.

2. Haul 770, Station xxii., 56 50' N., 3 59' E. Dredging made

July 24th, 1906, in 31 fathoms, on the Inner Shoal to the
S. of the Great Fisher Bank.

3. Haul 772, Station xxv, 56 34' N.', 3 53' E. Dredging made

July 24th, 1906, in 37 fathoms, to the S. of the Inner
\ Shoal and Great Fisher Bank.

/ B. Southern or Inner Area lying W. of the Dogger Bank,
between the Bank and the English coast.

4. Haul 869, Station xlii., 55 6' N., 1 2' W. Dredging made

July 23rd, 1907, in 43 fathoms, off Blyth, Northumberland.

5. Haul 871, Station xliv., 54 59' N., 1 7' W. Dredging made

July 23rd, 1907, in 34 fathoms, off Tynemouth.

6. Haul 882, Station (?), 55 21' N., 1 10 'W. Dredging made
\ July 26th, 1907, in 45 fathoms, off Alnmouth.

FROM THE NORTH SEA.

133

The asterisk denotes the presence of fossil specimens. 1 = a single
specimen only. V C = very common. C = common. F == frequent. R =
rare. VE = very rare.

MlLIOLIDAE.

Sub-family Nubecv larinae.

1. Xubecularia lucifuya Def ranee

Sub-family Miliolin inae.

2. Biloculina depressa d'Orbigny

3. Biloculina rinyens Lamarck sp.

4. Spiroloculina impressa Terquem

5. Miliolina bicomis Walker & Jacob sp

6. Miliolina circularis Bornemann sp.

7. Miliolina contort a d'Orbigny sp.

8. Miliolina seminulum Linne sp.

9. Massilina secans d'Orbigny sp.

Sub-family Pen eroplid inae.

10. Cornuspira involvens Reuss

11. Cornuspira Seise ye nsis Heron- Allen &

Earland ......

12. Cornuspira striolata Brady

13. Cornuspira diffusa Heron-Allen & Ear-

land

ASTRORHIZIDAE.
Sub-family Pilvlin inae.

14. Bathy siphon aryenteus Heron-Allen &

Earland

Sub-family Saccammininae.

15. Psammosphaeva fusca Schulze

16. Saccammina sphaerica M. Sars

Sub-family Bhabdamm in i nae.

17. Hyperammina ramosa Brad} r .

LlTUOLIDAE.
Sub-family Litvolinae.

18. Beophax dipluyiformis Brady

19. Beopha.v fusiformis Williamson sp.

20. Beophax nodulosa Brady

21. Beophax scorpiurus Montfort

22. Beophax Scottii Chaster

23. Haplophraymium anceps Brady

24. Haplophraymium Canariense d'Orbignv

sp

25. Haplophrayminm crassimargo Xorman

26. Haplophraymium pseudospirale William

son sp. .....

vc

c

vc

VR

VC

F

R

1*

c
vc

2

F

VC

R

1
VC

vc

F

1
1

5^ :

03 so

1

2

VR

R
F

VC
VR

VR

VC

5_-

F
R

R

2

VC

VC

1
VC

C

VR

VC
F

1

e

vc vc

3d

VR
VC

1
1

VR

134 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA

i

Sn

go

P <N

p

3^'

3

c3 ro

c3 t-

rit~

ci co

r-

=5 oo

r-

B"

s i -

K=

w

K 00

1

'.

2

3

4

5

6

Sub- family Trochammin inae.

27. Thurammina papillata Brady

1

28. Ammodiscus incertus d'Orbigny sp.

R

F

29. Trochammina ochracea. Williamson sp. .

F

C

R

vc

30. Trochammina squamata Jones k, Parker

F

VC

Textularidae.

Sub-family Textv lari nae.

31. Textularia agglutinans d'Orbigny .

VR

32. Textularia conica d'Orbigny .

VR

VR

vc

33. Textularia globulosa Ehrenberg

Y*

F*

1*

34. Textularia gramen d'Orbigny .

VR

35. Spiroplecta biformis Parker & Jones sp. .

1

36. Gaudryina filiform in Berthelin

-

F

R

37. Yerneuilina polystropha Reuss sp.

vc

R

VC

VC

VC

VC

38. Clavulina obscura Chaster

1

F

VC

Sub-family Bu limin inae.

39. Bulimina aculeata d'Orbigny

VR

R

c

40. Bulimina elegans d'Orbigny .

F

C

R

41. Bulimina elegantissima d'Orbigny

c

R

F

42. Bulimina fusiformis Williamson

vc

C

vc

VC

VC

VC

43. Bulimina marginata d'Orbigny

c

F

c

F

F

C

44. Bulimina, ovata d'Orbigny

F

45. Bulimina pupoides d'Orbigny

R

R

1

46. Virgvlina Schreibersiana Czjzek

R

R

47. Bolivina difformis Williamson sp.

VR

VR

1

48. Bolivina dilatata Reuss .

R

C

C

49. Bolivina nobilis Hantken

1

1

50. Bolicina plicata d'Orbigny

1

VR

F

F

51. Bolivina punctata d'Orbigny .

C

R

F

F

52. Bolivina textilarioides Reuss .

R

53. Bolivina variabilis Williamson sp.

R

F

Sub-family Cassibulin inae.

54. Cassidulina crassa d'Orbigny .

F

F

F

F

55. Cassidulina laevigata d'Orbigny

VR

R

1

56. Cassidulina subglobosa Brady.

R

R

F

Lagenidae.

Sub-family Lag en inae.

57. Lagena acuticosta Reuss

VR

58. Lagena apiculata Reuss sp. .

VR

2

59. Lagena bicarinata Terquem sp.

1

60. Lage?ia clavata d'Orbigny sp.

R

C

F

61. Lagena costata Williamson sp.

F

R

62. Lagena cymbula Heron-Allen & Earland

1

63. Lagena distoma Parker & Jones

1

R

C

VC

64. Lagena fasciata Egger .

R

VR

1

65. Lagena globosa Walker & Jacob sp.

1

VR

F

1

66. J^agena gracUlima Seguenza sp.

j

1

C

FROM THE NORTH SEA.

135

"'-' 5 3<* 2
~*- S l - K 1 - K

67. Lagena

68. Lagena

69. Lagena
Lagena

79. Lagena

71. Lagena
Lagena

72. Lagena

73. Lagena

74. Lagena

75. Lagena

76. Lagena

77. Lagena

78. Lagena

79. Lagena

80. Lagena
81 Lagena

82. Lagena

83. Lagena

84. Lagena

85. Lagena

gracilis Williamson .
hexagona Williamson sp.
laevigata Reuss sp. .
laevigata, trigonal form
laevis Montagu sp.
lagenoides Williamson sp.
lagenoides, trigonal form.
lineata Williamson sp.
lucid a Williamson sp.
Malcomsonii J. Wright
marginata Walker & Boys sp.
marginato-perforata Seguenza
Orbignyana Seguenza sp.
ornata Williamson sp.
quadrata Williamson sp.
se mist riat a Williamson
squamosa Montagu sp.
striata d'Orbigny sp. .
sulcata Walker & Jacob sp.
unguis Heron-Allen *Sc Earland
Williamsuni Alcock sp.

Sub-family Xodosarinae.

86. Xodosaria Jiliformis d'Orbigny

87. Xodosaria pan perata d'Orbigny

88. Xodosaria pltbeia Reuss.

89. Xodosaria p grula d'Orbigny .

90. Xodosaria scalaris Batsch sp.

91. Lingulina carinata d'Orbigny

92. Marginulina glabra d'Orbigny

93. Vaginuliiia legumen Linne sp.

94. Cristellaria acut auricular is Fichtel &

Moll sp

95. Cristellaria costata Ficbtel & Moll sp.

96. Cristellaria rotulata Lamarck sp. .

Sub-family Poltmorp hi n inae.

97. Polgmorphina compressa d'Orbigny

98. Polgmorphina lactea Walker & Jacob sp

99. Polgmorphina oblonga Williamson .

100. Polgmorphina sororia Reuss .

101. T'vigerina angulosa Williamson

102. Ucigerina pygmcea d'Orbigny

Olobigerixidae.

103. Globigerina aequilateralis Brady .

104. Globigerina bulla ides d'Orbigny

105. Globigerina cretacea d"Orbigny

106. Globigerina rubra d'Orbigny .

107. Pullenia xphaeroides d'Orbigny sp.

VC

1

R

ve

c

R

YC

F

F
F

VC

VC

1

1

R

1

VR
VE

C
VR

R

VR
VR

VR

1

VR

F

VC
VR

F

1*

R

1

VR

1

1*
R*

R

1
R

C

Y*

VC

X X

1

F
VC

c

VR

F

F

F

1
F

1

C
F
C
C
1

c

1
1*

\ T R*

1

2

1*
R

1*
C

1

VC

F

1

1

1
F

F

VC

C
R

C

1

c

R

VC 1
R

R

C

C

1

136 B. HERON-ALLEN AND A. EARLAND ON SOME FORAMTNIFERA

ROTALIDAE.
Sub-family Spj rillin inae.

108. Spirillina vivipara Ehrenberg

Sub-family Rotalinae.

109. Patellina corrugata Williamson

110. Discorbina Chasteri Heron-Allen & Ear-

land ......

111. Discorbina globularis d'Orbigny

112. Discorbina Mediterranensis d' Orbigny sp

113. Discorbina nitida Williamson sp. .

114. Discorbina obtusa d'Orbigny sp.

115. Discorbina Peruviana d'Orbigny sp.

116. Discorbina poly rraphes Reuss

117. Discorbina Praegeri Heron- Allen & Ear

land ......

118. Truncatulina lobatida Walker & Jacob

sp. .....

119. Truncatulina refulgens Montfort sp.

120. Truncatulina Ungcriana d'Orbigny sp,

121. Pulvimdina haliotidea Heron-Allen &

Earland .....

122. Pulvinulina Karsteni Reuss sp.

123. Rotalia Beccarii Linne sp.

124. Rotalia orbicularis d'Orbigny

NUMMULINIDAE.
Sub-family Poltstomellinae.

125. Nonionina asterizans Fichtel & Moll sp.

126. Nonionina depressula Walker & Jacob

SP

127. Nonionina pauper ata Balkwill & Wright

128. Nonionina scapha Fichtel & Moll sp.

129. Nonionina stelligera d'Orbigny

130. Nonionina turgida Williamson sp. .

131. Nonionina umbilicatula Montagu sp.

132. Polystomella striatopunctata Fichtel &

Moll, sp

133. Polystomella crispa Linne sp.

3*-'

VC

3

c

vc

vc

F

F

R
C

VC

vc
1

3

F

F

1

VC

R

C
C

R
VC

VC

2*'

VR

VR
C

F

R
VC

VR
C
1

VR

1

R
1

VR

C

R
C
R
C
F
C

C
VR

F
VR
VC

F

F
R
R
1

VC

CO

cc

c

1

1

c
1

R
C
F

1
R

C

1
F

1
F

C

FROM THE NORTH SEA. 137

DESCEIPTION OF PLATES.

Plate 10.

Fig. 1. Reophax nodulosa Brady, x 120.
2, 3, 4. Haplop>hragmium pseudospi?*ale Will, sp., x 40.
,, 5, 6. Haplophragmium crassimargo Norman, x 30.
,, 7, 8. Clavulina obscura Chaster, x 100.
9. Spiroplecta b iformis Parker & Jones sp., x 120.
10. Lagena cymbida Heron- Allen & Earland, superior view,

X 250.
11. Lagena cymbida Heron- Allen & Earland, inferior view,

x 250.
,,12. Lagena cymbida Heron-Allen & Earland, edge view,

x 250.
13, 14, 15. Globigerina rubra d'Orbigny, x 120.

Plate 11.

Fig. 1. Cornuspira diffusa Heron-Allen & Earland, x 5, illus-
trating the protean habit of growth.

2. Heavy portion of ooze from Hilte Fjord, Norway, 260
metres, " Goldseeker" Haul 141, depth 260 metres.
Most of the foraminifera have been removed by
elutriation, leaving a residuum of faecal pellets of
Annelid origin (1 Hyalinoecia sp.) x 45.

,, 3. Rounded sand-grains from "Huxley" material, x 12.

,, 4. Normal angular grains typical of shore gatherings and
shallow-water deposits, x 12.

,, 5. Crystalline sand-grains from a dredging in the Hauraki
Gulf, New Zealand, x 1 2. Such crystalline grains are
very rare except in the neighbourhood of volcanic
deposits.

[It is greatly to be hoped that the writers will find it possible
for them to examine in similar detail a certain number of the
remaining "Huxley" dredgings, of which some six hundred are
available, taken from the North Sea south of the Forth. Their
present paper shows that in their practised hands results of con-
siderable interest may be expected should this be done. I would

Journ. Q. M. C, Series II. No. 73. 10

138 E. HERON-ALLEN AND A. EARLAND ON SOME FORAM1NIFERA.

submit for their consideration the examination of selected stations
along lines drawn east and west, in the manner of sections. A
large proportion of these in all probability could be dealt with
in a very summary manner, but the remainder might yield
results of importance as to the relation of distribution to salinity,
depth, temperature and current, possibly even affording evidence
of the main trend of the currents, which would provide a welcome
check on other observations carried out by current-meters and
drift -bottles.

In regard to the samples which they have examined from
the deep water east of the Dogger it may be remarked that the
Admiralty tide charts show but low rates of velocity in the
district, which has moreover a greater depth of water than one
would expect to be consistent with frequent wave action at the
bottom. Recent current measurements carried out by the
Board of Agriculture and Fisheries have also failed to detect
any marked resultant current. It may therefore be suggested
that the sub-polish attained by the rounded grains is not in
all cases due to attrition on the spot. The freedom of the
adjacent Dogger Bank from silt, a grade of material found in
high percentage on either side, may perhaps be explained by
the finer particles churned up and held in suspension by wave
action during storms being gradually washed into the deeper
water : some segregation of the rounder grains may take place
in the same manner. A thorough geological examination of
the area, especially of the Scottish coast, might also show to
what extent, if any, the grains result from the disintegration
of certain definite sandstone rocks.

For the action of wave and current in the Southern Bight
(North Sea south of 53) the collection of samples as a whole
furnish good evidence ; the material is to a great extent graded
as in a levigator, the average diameter of the sand particles
diminishing as the speed of the current declines. Yet even in
this district, with its shallower waters and far more powerful
currents, the upper limit of size of the particles affected is soon
reached, and one feels in consequence the need of searching for
other causes before explaining the rotundity of certain of the
grains near the Dogger by tidal action alone. J. O. Borley.]

r . , . _____ _ , _,

jQurn. Quefcett Mkyo-icopical CliLib, Ser. 2, YoLX.IL, Np. 73, November ]>Z3,

Journ. Q.M.C.

Ser. 2, Vol. XII., PI. 10.

FORAMINIFERA FROM THE NORTH SEA,

Tourn. Q.M.C.

Ser. 2, Vol. XII., PI. 11.

BpX^Smt

N

A^fc. ^*> ^? 1

P>

',.

*^ . -

IF

i^E^L^^

.4

t?

P^B . a^P^H P^PAw^a. .^^Pmb ^1 P^H t *^? 1
^^^B PMV PS -k^_ fi^W

Bp^^^ r m ^ J

BS^; Kpjfe/w ^^^^ Pfet. ^

W*iM PJ*V^ PA. 3L > Bl

4 fe^ ^

CORNUSPIRA DIFFUSA HERON-ALLEX AND EaRLAND.

Sand-grains, etc., from the Bottom-deposits,

139

DESCRIPTION OF ARRHENURUS SOOURFIELDI AND
ACERCUS LONG/TARSUS : TWO NEW SPECIES OF
WATER-MITES.

By C. D. Soar, F.L.S., F.R.M.S.

(Read April 22nd, 1913).

Plates 12, 13.

Arrhenurus Scourfieldi sp. nov.

In the autumn of 1912, Mr. D. J. Scourfield handed me a tube
containing a few water-mites, which he had taken from fresh
water in Cornwall. Amongst them was one which was quite new
to me, a male Arrhenurus, of the sub-genus Megalurus. As I
cannot find that it has been described or figured, I propose to name
it after Mr. Scourfield.

Arrhenurus Scourfieldi sp. nov. The specimen is a male ;
length 1-04 mm., greatest breadth about 064 mm. In outline
the body is long ; anterior corners well cut off, and slightly bent
inwards ; sides almost straight, tapering towards the posterior
margin. The posterior margin is divided by a central cleft into
two well-rounded portions.

The skin is covered with small papillae ; the dorsal surface has
the usual indented sunk line common to members of this genus,
and several dermal glands both inside and outside the sunken line.
Looked at from above there is a small wing-like process about
0'15 mm. from the posterior margin.

The colour is a dark blue-green with brown markings on the
dorsal surface. The epimera are slightly lighter in colour. It
is of the same colour as Arrhenurus globator.

The eyes are very dark red, close to margin, about 0*32 mm.
apart. Capitulum, about 0"20 mm. long.

The first pair of epimera are joined together at the back of the
capitulum, the second pair pressed close to first pair so that what

140 C. D. SOAR, DESCRIPTION OF ARRHENURUS SCOURFIELDI AND

is known as the first two pairs of the epimera form one distinct
group.

The posterior pair are in two distinct groups placed about
0*05 mm. behind the second pair.

The genital area lies about 0*08 mm. behind the fourth pair of
epimera, the plates stretching the whole distance across the
body of the mite. The length of each plate is about 0*25 mm.,
tongue shaped and covered with numerous acetabula.

The legs are of the usual structure of the genus with the spur
on the fourth segment of the fourth leg. They are strong and
well provided with swimming hairs. The first leg about 0"60 mm.
long, fourth leg 0'84 mm.

Locality : Near the Lizard, Cornwall, 1912. Female unknown.

Acercus longitarsus sp. nov.

Acercus longitarsus sp. nov. The body is 0*76 mm. in length ;
breadth about 0'54 mm., ovate. The colour is a pale straw
yellow with dark-brown markings. There is a reddish-yellow
wedge-shaped patch in the centre of the dorsal surface.

The epimera cover nearly the whole of the ventral surface, and
differ from that of the type species Acercus omatits in the follow-
ing important particulars. Firstly, the genital area instead of
being situated in a small bay on the posterior margin of the
epimera as in Acercus ornatus, is partly enclosed in an angular
space formed by the posterior edge of the epimera being turned at
a low angle towards the median line. Secondly, near the base
of the epimera are two small incurvations, one on each side, which
are not found in the type species of this genus. They run into
the epimera about O05 mm. The actual genital area itself is
similar to type species, having six acetabula arranged in the same
way.

The palpi are about 0*45 mm. in length. On the flexar edge
of the fourth segment are placed two long hairs, a little distance
apart ; they are close together in Acercus ornatus.

The legs of the species form the most striking departure from
the type form and in fact all other species of this genus ; on
comparison it will be seen that the tarsi are enormously developed
in length.

The last segment of the first and second pairs of legs are longer

ACERCUS LONGITARSUS \ TWO NEW SPECIES OF WATER-MITES. 141

than usual, but it is the last segment of the fourth pair which
shows the great increase in length. The tarsi measure as much
as 0*60 mm., which is more than the fourth and fifth segment
together.

The first leg is about 1*40 mm. in length, the second about 1*30,
the third about 0"90, the fourth about 1-58.

The eyes, large and distinct, are very dark red and about 0'14
mm. apart.

This mite can be most easily recognised by the length of the
tarsus of the fourth pair of legs. I propose naming it Acercus
longitarsus.

Locality : South Devonshire (female unknown).

There are also one or two additions to be made to British
records. Mr. Williamson, F.R.S.E., in working out the material
on the Genus Sperchon, has found that we have two species quite
new to the British area, and two that up to the present have only
been recorded for Ireland.

1st. Sperchon clupeifer Pier.
Sub-genus : Hispidosperchon.
Locality : Oban and Norfolk Broads.

2nd. Sperchon tenuabilis Koen.

Sub-genus : Hispidosperchon.

Locality : Oban. Recorded for Ireland by Halbert in Clare
Island survey.

3rd. Sperchon papillosus Sig Thor.
Sub-genus : Squamosus.
Locality : Oban. Recorded for Ireland by Halbert.

4th. Sperchon Thienemanni Koen.
Sub -genus : Rugosa.
Locality : Derbyshire.

142 c. d. soar, description of two new species of water-mites.

Description of Plates.

Plate 12.

Fig. 1. Arrhenurus Scourfieldi sp. nov. Dorsal surface of male
drawn from a living specimen, x 50.
2. Arrhenurus Scourfieldi sip. nov. Ventral surface of same
drawn after mounting.

Plate 13.

Fig. 1. Acercus longitarsus sp. nov. Dorsal surface of males,
X 58.
2. Acercus longitarsus sp. nov. Ventral surface of same,

x 58.
3. Acercus longitarsus sp. nov. Palpi of same, X 150.

Jovrn. Quelett Microscopical Club, Ser. ?, Vol. XII., Ho. 73, November 1913

Journ. Q.M.C.

Ser. 2, Vol. XII., PI. 12.

^A7 2

C. D. S., del. adnat.

$ Arrhenurus Scourfieldi sp. nov.

Journ. Q.M.C.

Ser. 2, Vol. XII., PI. 13.

C. D. S., del. ad nat.

S ACERCUS LONGITARSUS sp. nOV.

143

THE COLLECTION AND PRESERVATION OF THE

HYDROIDA.

By G. T. Harris.

Communicated by C. J. IT. Sidwell.
{Bead April 22nd, 1913.)

The Hydroida are too well known, as both beautiful and interesting
objects, to need any eulogy on my part. If they have received
less attention from the members of the Q.M.C. than some other
groups, it is probably due to the fact that the Hydroida evince
a decided and conservative preference for salt water, and show
no inclination whatever for the uneventful environment of
metropolitan ponds. Hence, those who would collect them must
seek them where they may be found, i.e. from tidal limits to as
many fathoms as the collector's means or stomach will allow.

Bearing in mind that this paper is written more for the help
of the novice than as a communication offering original matter,
I would safeguard myself from any charge of carelessness by
warning the uninitiated that collecting, say, rotifers, and col-
lecting hydroids are two totally dissimilar things. Pond
collecting is a more or less safe and a very pleasant recreation ;
hydroid collecting is rarely enjoyable, and may be, by a little
carelessness, rendered adventurous. The one could be prosecuted
in a silk hat and a frock coat if desired, without seriously giving
the wearer away ; the costume best suited to the other tries the
loyalty of one's staunchest friend. Dredging is, perhaps, less
open to contumely than shore collecting ; the nature of the
operation secures to the collector a considerable measure of
privacy, while the examination of the spoil can be carried out
in attitudes familiar to oneself and those around. Shore collect-
ing permits of no compromise, and the positions most consonant
with successful collecting are mainly such as contribute materially
to the entertainment of the seaside visitor waiting to be
amused.

I think it may be taken for granted that, in spite of its

144 G. T. HARRIS ON THE COLLECTION AND

obvious drawbacks, shore collecting will appeal to the amateur
collector rather than the more professional method of dredging.
It entails less expense, requires less intimacy with the local
conditions, and, for a given amount of time expended, probably
yields a richer harvest ; finally, the physiological effects of shore-
collecting are not so overwhelming as are those sometimes
connected with dredging. At the same time, no serious student
of the Hydroida can ignore the dredge as a means of collecting,
as a large number of species can only be obtained by its aid.
However, for the reassurance of those who confine themselves to
shore collecting, I may state, as the result of long experience,
that on a favourable shore the number of species to be found
between tide-marks is very great, and amongst them are many of
the most beautiful forms amongst the Hydroida. -

Unfortunately no precise directions can be given for successful
shore collecting. It is entirely a matter of experience, and even
the practised collector may fail dismally until he has learnt the
shore upon which he is engaged. Why hydroids should be found
plentifully in a certain section of shore, yet be absent from the
same shore a quarter of a mile away, with apparently the same
conditions, I am unable to say, yet such appears to be the case. In
my own district, where rock-pools are plentiful, I have a case
in point. Coryne vaginata, one of the commonest littoral
hydroids along the south coast, occurs in two or three of the
larger pools of a certain locality, yet although the rock-pools to
the right and left for some distance are, as far as I can see,
identical, no Coryne occurs in them. Nor is this accidental, or
peculiar to one season, as I have been able to go to these
particular pools for the last six years with the certainty of
obtaining Coryne vaginata. Some years ago when collecting at
Criccieth, in North Wales, I spent day after day laboriously
trying to collect hydroids where none grew ; finally, I transferred
my operations to a less likely looking section of the shore, and
collected hydroids during the remainder of my visit over a very
limited area. An instance singularly illustrative of this elusive
quality of shore collecting recently came under my notice, which
may serve to impress upon inexperienced collectors the desirability
of not jumping too hastily to the conclusion that they are on a
barren shore. A party of professional naturalists spent the
whole of one summer in investigating the fauna of a certain

PRESERVATION OF THE HYDRQIDA. 145

section of coast, the results of which were embodied in a report.
The shore collecting was apparently confined to one spot, from
which but one hydroid, and that the ubiquitous Sertularia pamila,
was recorded ; yet a quarter of a mile farther east is an excep-
tionally prolific hunting-ground at low tide, where at least a
dozen species of hydroids may be taken. All this points to the
fact that wherever the hydroid-hunter elects to collect he must,
as a preliminary, first ascertain that he has found the hydroid
ground. When he has satisfied himself that he has done so, then
collecting may begin in earnest.

It is too readily assumed that only those shores are good for
hydroid-hunting upon which rock-pools occur. My experience
leads me to protest against this assumption, for I have often
had much better collecting on shores strewn with large fucus-
covered boulders than in some rock-pool districts. Rock-pools do
not necessarily imply the existence in them of hydroids, not even
when they are clean, sanitary abodes. The rock-pools at Sid-
mouth are excavated in Permian sandstone at the base of cliffs
500 ft. high, composed principally of Keuper marl, and in the
early summer are lined, as is everything in them, with fine
mud, the result of the red marl falling from the cliffs during
winter and being washed into the pools. This should make
hydroid life impossible, but it does not ; they seem to thrive in
it (I sometimes think upon it), and cleaning them for the
microscope thoroughly disheartens one. Last autumn I was
collecting in South Devon, where the cliffs are composed of
hard conglomerate, giving fine clean rock-pools. One rock-pool
near low-water mark especially attracted my attention. Filled
with clear, limpid water, its sides draped with seaweeds, every
condition seemed perfect for hydroid life, and yet not a single
specimen was found in it. I satisfied myself of this by abso-
lutely cleaning the pool out, examining every piece of seaweed,
as I removed it, in a small tank of water, then going carefully
over the sides and bottom of the pool with a lens of large
diameter. It is little discrepancies like these that both try and
puzzle the shore collector.

Hincks has given advice upon shore collecting that cannot
well be improved upon, and is as precise as such advice can
be. He recommends lying at full length when collecting, and
however objectionable this may seem to be in theory, it is

146 G. T. HARRIS ON THE COLLECTION AND

thoroughly sound in practice, and I always adopt it, carrying
a mackintosh sheet for the purpose. It should be recollected
that a superficial examination of any rock-pool is not sufficient
to detect minute species, and even species of considerable size,
such as Plumularia setacea, often harmonise so well with their
surroundings as to be difficult of detection. As far as possible
it is best to assume a comfortable position, and then thoroughly
examine the basin and the seaweeds it contains, using a lens of
about 4 inches diameter when necessary. Many rock-pools have
projecting ledges draped with fucus ; such are found to be espe-
cially prolific if well examined. The fucus should be turned
right back, so as to expose the sides it covered and the under
surface of the ledge, which are normally in deep shade. Sponges
growing underneath may be scraped off and examined for com-
mensal hydroids. If long, dark tunnels exist in the rock, the
arm should be pushed up and the upper surface of the rock felt
over with the hand for any adherent masses of sponge, etc.,
which may be broken off and examined. This is a distinctly
sporting method, as it gives the crab, when there, a chance to
get in first with his pincers. Bring him out and hold him under
water in the rock-pool while you go over him carefully with a
lens ; his carapace will probably recompense you for the pinched
finger. Shells, also, should be carefully examined. The only
time I ever took Podocoryne areolata was upon a shell found lying
at the bottom of a funnel-shaped rock-pool, and Professor
Allman had the same experience. Many species are so minute
as to defy detection by the ordinary methods of shore collecting
and are best obtained by taking small tufts of seaweeds and
looking over them at home with the compound microscope.

I have remarked previously that collecting is often very re-
munerative on shores strewn with large fucus-covered boulders.
Those who know Llandudno and Criccieth will recognise excellent
examples of such shores, and doubtless many similar exist round
the coast. The boulders near low-water mark yield the richer
harvest, and the underneath is the surface to work. Where
two of these huge boulders have fallen close together, so as to
form a miniature tunnel, the latter is sure to afford a prolific
hunting-ground. My method is to lie on my back and gradually
work into the tunnel, carrying a blunt knife and some fair-sized
bottles, or jars, of sea-water, The surface of the rock is chipped,

PRESERVATION OF THE HYDROIDA. 147

or scraped, where promising growth appears, and the gathering
dropped into the bottles, to be examined elsewhere and in a
more comfortable position. This is really an excellent method
of obtaining material.

Dredging is not likely to be undertaken by the occasional
collector unless he is a very enthusiastic one, and if undertaken
the individual will probably be in no need of advice from me, as
he will know more or less about it. To the beginner I would
say, choose a dredge of moderate size and confine dredging
operations to moderate depths, i.e. up to ten fathoms. If any
fishing industry is carried on where the collector happens to be,
he may get ample employment from a bucket of trawl refuse
obtained from one of the boats ; even the rejectamenta of
lobster-pots is a good hunting-ground. On an open sandy coast,
after a gale or heavy sea, deep-water specimens may be obtained
in excellent condition if the jetsam left by a receding tide is
carefully looked over. They should be promptly placed in bottles
of sea-water, to recover and expand their tentacles, and this
process may be aided by vigorously aerating the water by means
of a syringe.

Having collected the material, the less eventful work of pre-
paring it for the microscope follows as a matter of course, and
I believe I am doing beginners a service in urging upon them
the desirability of arranging for this to take place at the earliest
possible moment after collecting. Once the hydroids begin to
feel the effects of overcrowding and badly aerated water the
polyps withdraw into their calycles, and require a large expendi-
ture of time and patience to coax them to expand again. The
best results are undoubtedly got when the collector is in a
position to go straight from the shore to his microscope and deal
with the material collected. The polyps are then vigorous from
their normal environment, less intolerant of the narcotising
agent, and a considerable quantity of material can be dealt with
in a comparatively short time, as there is no tedious waiting
for the polyps to expand. My own method is to divide the
collection into two lots, separating the Gymnoblastea from the
Calyptoblastea, as the former can be best prepared by killing
without the intervention of a narcotic. The hydroids are placed
in watch-glasses (or better still small Petri dishes) with clean
fresh sea- water, and cleansed as far as can be without injuring

148 G. T. HARRIS ON THE COLLECTION AND

the polyps by gently brushing the polypary with a camel's hair
brush. They are allowed to recover from the shock, and then
a few drops of 1-per-cent. cocain hydrochlorate added to each
watch-glass and the glasses set gently aside until all the species
have been dealt with. When the polyps are fresh and vigorous
narcotisation is not a difficult process, nor one requiring extreme
care, but should the hydroids be left twenty-four hours or so
before dealing with them the process is likely to be not only
tedious but generally unsuccessful. When the polypites are
judged to be sufficiently narcotised to permit of killing the
tentacles should be pricked with a needle somewhat roughly, to
be quite certain that narcotisation is sufficient to prevent retrac-
tion of the tentacles. I learnt by experience that even when
insensibility was apparently well established, on the application
of the killing and fixing agent the polypites would withdraw at
least partially, perhaps wholly, into the calycles, so that it is
necessary to be quite sure that narcotisation is complete before
using the fixing fluid. The killing and fixing agent most con-
venient is undoubtedly osmic acid, either a plain 1-per-cent.
solution or combined with platinum chloride as in Hermann's
solution. I have tried many other solutions for this purpose,
but found none more suitable. The osmic-acid solution is sprayed
over the colony in the watch-glass with a pipette and allowed to
act for several minutes, when it is washed away by repeated
changes of clean fresh water, allowing the specimens to soak in
each wash water for some time. Finally they are given a
weak bath of hydrogen peroxide or potassium ferrocyanide, to
thoroughly eliminate the acid, and again well washed. This is
the procedure for Calyptoblastic hydroids, the Gymnoblastic
may have a little more cavalier treatment. If narcotisation is
attempted with them it has the effect of causing them to
gradually shorten the tentacles, and once that has taken place
they never extend them again while under the influence of the
narcotic. This being the case the best method is to kill them
suddenly with an energetic killing agent while fully expanded.
Some retraction of the tentacles may take place in the killing,
but to nothing like the extent that would happen if narcotisa-
tion were attempted. It is unfortunate that mono-bromide of
camphor is insoluble in sea-water, as I am convinced, from the
admirable results it gives with Cordylophora and Hydra, that

PRESERVATION OF THE HYDROIDA. 149

it would form an excellent narcotiser for this division. Lang's
fluid is a good killing agent for the Gymnoblastea, and, of course,
assists staining if carmine is used. Picric acid also answers well ;
and osmic acid or Hermann's solution if the specimens are not
too large, otherwise I have found the killing occupy sufficient
time to permit of considerable contraction.

Undoubtedly the great difficulty in preparing hydroids for the
microscope lies in getting clean mounts that is, supposing clean
mounts are desired and this difficulty becomes augmented with
material from between tide-marks. The polyparies are generally
encrusted and overgrown with an olla podrida of marine life, so
that the mount really becomes a compound object. To me
this is anything but a drawback, providing, of course, that no
essential part of the hydroid is masked. On some shores, how-
ever, the amount of material collected is out of all proportion to
its interest, and it becomes necessary to subject it to a cleansing
process. This should be done before narcotising and killing the
hydroid, otherwise the tentacles are liable to be injured and
entangled. The polyps withdraw into their calycles during the
application of the brush, but soon recover from their fright when
placed in a glass of clean fresh water and allowed to rest quietly
for a time.

If staining and mounting fixed material are deferred until a
more convenient time, it has to be stored in some preservative
fluid ; formalin at once suggests itself, for which reason I
wish to utter a word of warning. Formalin is perfectly satis-
factory for objects that are to be mounted unstained, as they
will eventually find a permanent home in this medium, but
personally I have not been successful in staining material that has
been stored for some months in a 5-per-cent. solution of formalin.
This, of course, may be due to some error peculiar to myself, but
I would offer this warning to inexperienced workers. If time
and facilities allow I would strongly advise the beginner to stain
straight away, and if unable to mount, then store the stained
material in 70-per-cent. alcohol. Tailing this, I think it prefer-
able to store those hydroids destined for staining in 70-per-cent.
alcohol. In storing avoid the error of putting too many into one
tube ; small tubes with a few in each are very much better than
a heterogeneous collection of species in a large tube or bottle.

The microscopist will doubtless have his own pet stain or stains,

150 G. T. HARKIS ON THE COLLECTION AND

and as a good general stain is all that is required for systematic
work it does not much matter which is used. I have used
principally para-carmine, carmalum and haemalum of Mayer's
formulae; the last of which I prefer on account of its better
visual properties, also because it stains exceptionally well objects
that have been fixed with osmic acid. I may here mention that
haeniatoxylin has been regarded by some workers as a fugitive
stain ; why, I am unable to discover. I attempted to bleach
some slides that had been over-stained by exposing them for some
months in a window with a south aspect, and at the end of that
time withdrew them as hopelessly permanent. They should have
faded, according to all the authorities, but much to my disgust
they did not.

For unstained objects I use excavated slips, and a 2^-per-cent.
solution of formalin. A ring of old, fairly thick gold size is run
round the edge of the hollow and allowed to become nearly dry, at
least dry enough to retain the impression of a scratch made with
a needle. The selected portion of the hydroid colony is placed in
the cell, and 2|-per-cent. formalin solution added until a full cell
with a convex surface to the fluid is obtained. The cover-glass is
then placed in position, expelling the superfluous formalin. Under
a mounting microscope, with a strong blunt needle, the cover-
glass is pressed into intimate contact with the ring of gold size,
until it can be seen that no lacunae exist between it and the cover-
glass. The extraneous formalin is now removed and the slide
allowed to dry, when several rings of gold size may be applied.
Slides so prepared have attained the comparative antiquity of
sixteen or eighteen years without showing any deterioration.

As this paper has been prepared with the object of placing
practical information before those desirous of devoting some
attention to our hydroid fauna, it may not be considered alien to
the subject if I refer briefly to various localities of which I have
personal knowledge, from collecting more or less frequently in
them ; merely premising that my acquaintance with them as
collecting-grounds has been more by accident than design, and I
have no wish to suggest that they are any more desirable from
the collector's point of view than numbers of others unknown to
me. In North Wales my collecting-stations have been Llandudno,
Menai Straits, Criccieth and Barmouth. Llandudno and Criccieth
are excellent grounds. The rocks at I4andud.no under the Great

PRESERVATION OF THE HYJDROIDA. 151

Orme afford plenty of work at low tide, but rock-pools are
practically non-existent ; I have taken many good northern
species from the under-sides of the boulders strewn about.
Criccieth is a capital ground ; the rocks on the shore at the foot
of the Castle Hill repay the most ample attention, yielding many
and good species. A short distance from Criccieth are the Black
Rock caves, which are really a paradise for the shore collector,
but are only accessible at low tide. The Menai Straits, also, have
good collecting-spots on the rocks at the Suspension and Tubular
bridges, but the drawback to work thereabouts is the swiftness of
the tide, which makes boating difficult and risky unless accom-
panied by a local boatman. Pennington collected many species
between the two bridges. Staithes, in Yorkshire, has a good
shore for collecting, as the rock-pools are ample. Coming now to
Devonshire, with whose shores I have intimate acquaintance, we
reach ground made classic by the labours of Gosse, Hincks,
Allman, Kingsley, Montagu and many others. Ilfracombe, in
North Devon, has the advantage of clear rock-pools, in places an
almost vertical rise and fall of tide, and excellent boating and
dredging. As it has received its meed of praise at the hands of
such authorities as Hincks and Gosse, not to mention Lewes, it
may be considered sufficiently hall-marked. Torquay, Gosse's
home and hunting-ground par excellence, is indubitably an ideal
district ; I know no better. The collecting at the Corbon's Head
alone will occupy a long holiday, and the coast under Livermead,
Kingsley 's one-time residence, is honeycombed with charming
rock- pools full of hydroid life. At Brixham one gets in touch
with a tiawling district, and plenty of chances occur of going
over trawl refuse. In East Devon, from Exmouth to Sidmouth,
the naturalist has to set a watch on his lips, for the combination
of excellent rock-pools and cliffs of Keuper marl is more than the
average shore collector can bear unmurmuringly. At the same
time, the fauna of these rock-pools is both luxuriant and diversi-
fied ; and one has to remember that it was principally in East
Devon that Hincks collected both hydroids and Polyzoa.

I would conclude with an apology for the extremely elementary
nature of this paper. It is a mere account of personal methods,
offered to the inexperienced in the hope of smoothing away some
of those preliminary difficulties that appear to be " commensal "
with the early days of all new subjects.

152 g. t. harris on the collection and

Notes on Some Species of Hydroida, principally intended
for Purposes of Identification.

Clava multieomis.

The polypites in this species are scattered, not grouped as in
the next.

Clava squamata.

Polypites in groups, clustered, gonophores in dense clusters at
base of tentacles.

Clava cornea.

Clusters of polypites much smaller than in C. squamata, gono-
phores smaller and less densely clustered. The two species are
closely allied, and Dr. T. S. Wright considered cornea a variety
of squamata.

Podocoryne areolata.

Apparently a rare species, as Hincks only records it from three
localities. It is easily distinguished by the sessile gonophores
being borne on the chitinous expansion of the stolon.

Coryne vaginata.

The common species of the south coast, and may be recognised
principally by the cup-like membranous expansion of the polypary.
It is essentially a rock-pool species.

Coryne pusilla.

In this species the tentacles are " more truly whorled than in
any other form of Coryne " (T. H.). The polypites are linear in
shape, and "of about equal size from one extremity to the other "
(T. H.). The only specimen I have ever had was found in some
material sent from Marazion.

Eudendrium ramosum.

The height given for this species by Hincks is "about
6 inches," but it appears to become dwarfed as it nears a littoral
habitat.

Eudendrium insigne.

In the absence of gonophores the specific name can only be
given with considerable hesitation. Hincks states its habitat

PRESERVATION OF THE HYDROIDA. 153

"to be between tide marks on the south coast, and mentions
a circular groove near the base of the body as a means of
identification.

Perigonimus sessilis.

The only species with ringed coenosarc. The polyp not dilated
underneath the tentacles.

Bougainvillea muscus.

Allman distinguishes this species by its small, habit and the
fact that its stems consist of a single tube, instead of being
composed of several tubes coalesced into one. The records for
this species seem to be very scanty.

Clytia Johnstoni.

The pedicel in this species is usually ringed at the top and at
the bottom, being smooth in the middle portion. Some specimens
are, however, more or less ringed throughout.

Obelia geniculata.

This species is readily distinguished by the projections sup-
porting the ringed pedicels bearing the hydrotheca.

Campanularia neglecta.

The margin of the calycle in this species is crenulate. This
can only be seen with difficulty, as it is so readily damaged.

Halecium Beanii.

It may be easily identified when bearing female capsules by
their distinctive shape and the short tubular orifice in the middle
of the capsule.

Sertularia filicula.

This hydroid varies in the position of the calvcles on the stem,
some being placed oppositely, and some more or less alternately.
It may be distinguished by the single erect calycle in the axils
of the branches. It is a deep-water species (20 fathoms), and
more especially a northern species. Hincks never met with it
in Devon or Cornwall, so its occurrence in rock-pools at Sidmouth
is somewhat noteworthy.

Jourx. Q. M. C, Series II. No. 73. 11

154 G. T. HARRIS, COLLECTION AND PRESERVATION OF THE HYDROIDA_

Plumularia pirmata.

The Plumulariidae are somewhat difficult for the beginner to>
separate, owing to the superficial resemblance of one species with
another. The most -trustworthy means of separating the species
is by a careful observance of the nematophores and distances of
the calycles. In P. pinnata the nematophores are very minute,
and lack the pronounced calycle present in other species, and.
are one below each hydrotheca. The gonothecae also, when
present, help materially in distinguishing the various species.
In the present species they are ovate, with spinous projections
on the top.

Plumularia setacea.

It somewhat resembles the former species, but the nema-
tophores are very different, being of superior size and differing in
number. The gonothecae are quite different, being flask-shaped ;
their axillary position also is an aid to diagnosis.

Plumularia echinulata.

In this species the pinnae have an unmistakable arched form
which does not occur in the others. The nematophores are
smaller than in P. setacea, and one nearly always occurs in the
axils of the pinnae. The gonothecae, however, when present
readily determine the species.

Plumularia similis.

This appears to be very near the former species (P. echinulata),
but the gonothecae are totally dissimilar, being without the
spinous projections.

Plumularia halecoides.

A minute species, and easily overlooked, The polypites have-
been compared to an hour-glass in shape. The gonothecae are
transversely ribbed. Nematophores very minute and difficult to
detect.

[The above notes are intended for use with a series of slides
presented to the Cabinet by Mr. G. T. Harris.]

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 73, November 1913.

155

THE MINUTE STRUCTURE OF COSCINODISCUS ASTER.
OMPHALUS AND OF THE TWO SPECIES OF
PLEUROSIGMA, P. ANGULATUM AND P. BALTICUM

By T. A. O'Donohoe.

{Read May 28th, 1913.)

Plate 14.

In preparing this paper it was, at first, my intention to refer in
no way to the work of others, of which, in fact, I had very little
knowledge. It has, however, been pointed out to me that it is
desirable to mention previous researches, in order to enable the
reader to compare these more easily with my own. Happily
Mr. E. M. Nelson gives a brief summary of his work on the
valve of Pleurosigma in a note read at the Club on January
28th, 1913 (Journ. Q. M. C, vol xii., p. 98). This note is
therefore easily accessible to all my readers, and any further
reference to it by me would be unnecessary. I regret I cannot
so easily dispose of the observations of Mr. T. F. Smith, who
has for many years devoted much time and thought to the
structure of diatoms, and who has so recently as August 1911
and October 1912 contributed to Knowledge two papers on this
much-discussed subject, entitled " The True Structure of the
Diatom Valve." These papers contain very many photo-
micrographs, of which several are excellent. I very much
regret, however, that I cannot agree with what I must call
his heterodox views. In his own words, "The points desired to
be driven home in the present article are that diatom structure,
consists of neither beads nor perforations as commonly under-
stood " (page 291).

Speaking of Pleurosigma for mosum, he says: " It appears to
consist of a series of chains, as it w-ere, formed of short bars or
fibrils of silex, arranged lengthways on the valve. They run in
pairs, parallel, each pair having larger and narrower interspaces
between them in regular succession, and so placed that the larger
interspaces are set obliquely to the corresponding interspaces
between the other pairs both above and below." A few lines
farther on he tells us that " his theory is this, that what we see
in the Pleurosigma valve when sound is not the structure at
all, but simply a collection of focal images thrown from the other

156 T. a. o'donohoe on the minute

layer upon the one nearest the eye, just as a picture is thrown
from the optical lantern upon a canvas screen. The fibrils or
grating is the real structure, of which the texture is concealed,
even as that of the canvas screen is concealed by the picture."
So much for this new theory. We can consider only a few of
its points. The figures given on page 289 are, we are told,
photomicrographs of the two separated membranes of a valve of
Pleurosigma angulatum. If two really good photographs were
taken of these two membranes at about 4,000 diameters, they
would, in my opinion, make an end of Mr. Smith's theory, but
instead of giving his readers two such images, which would be
extremely interesting and valuable, he gives them a great
number of outers ides and innersides which, he tells us, do not
show the structure at all, and are therefore of very little value.
Indeed, I may say for myself that I attach little or no value to
interpretations of fine diatomic structure other than those of
thoroughly separated single membranes. Of these only can we
speak with a fair degree of certainty.

Turning now to page 331, we find that Mr. Smith says : " Fig.
14 is from an innerside of another valve (of P. formosum), the
first ever seen and taken, showing the fracture through un-
doubted perforations," and Mr. Nelson, being called to his aid,
testifies that " Mr. Smith has found this fracture, had shown it
to him, and that at any rate the fracture did run through the
holes." So, too, Mr. Smith cites the testimony of Dr. Dallinger,
who says : " In Plate I. fig. 1 (Carpenter on the Microscope) we
have a photograph of his showing the inside of a valve of
Pleurosigma angulatum magnified 1,750 diameters, exhibiting
the " postage-stamp fracture." The postage-stamp fracture is,
as everybody knows, a fracture through the holes, so that we
have these two great authorities testifying to the fact that these
photographs of Mr. Smith show fractures through holes, or, as
Mr. Smith calls them, undoubted perforations. His theory being
that there are neither holes nor beads in the valve of a
Pleurosigma, does he now repudiate these photographs and
these testimonies'? He speaks of his fibrils forming interspaces,
chains and gratings, and it would be interesting to have his
definitions of these terms. Can there be chains or gratings
without intervening spaces, i.e. holes or perforations ?

Fig. 18, page 333, " The innerside of Pleurosigma angulatum

X 3,770," by no means a sharp image, shows, nevertheless, holes

galore to any one who is not blind or unwilling to see them.

STRUCTURE OF C0SC1N0DISCUS AsTEROMPHALUS, ETC. 157

Mr. Smith's second paper (October 1912) I cannot touch : the
exigencies of space forbid.

I am indebted to two members of the Club for the loan of two
slides realgar mounts which have enabled me to study the
minute structure of Pleurosigma angulatum and Pleurosigma
balticiua. Having taken several photographs from a slide lent
me by my friend Mr. Bruce Capell, I showed some of them to
our Secretary and Editor, and the latter informed me that
Mr. Nelson was engaged more or less on the same subject, and
suggested that I should send him copies of my photographs.
This suggestion I fell in with the more readily inasmuch as it
would give me the benefit of any adverse criticism which Mr.
Nelson might feel himself called upon to make. To elicit this I
wrote on the back of each a brief interpretation of the structure,
and in one case in which I was much puzzled I placed a note of
interrogation. With his usual kindness and urbanity, Mr. Nelson
gave the desired information, but instead of adverse criticism he
sent me two slides of great historic as well as intrinsic value.
From these I have been enabled to make some photographs
which confirm the results already obtained from the slide belong-
ing to Mr. Bruce Capell.

Coming now to my immediate subject, my readers are, no
doubt, aware that Dr. Van Heurck tells us that a diatom valve
consists of two membranes and of an intermediate laver which he
calls a septum, and that it is this latter layer which contains the
cavities or perforations. In my opinion this definition connotes
at once too much and too little : too much by giving the valve
three layers, and too little by confining the cavities to the septum
only. In the three valves which we are about to consider, I find
only two layers or membranes, each of which has its own perfora-
tions. We will, in the first place, consider the structure of
C oscinodiscus asteromphalus. The photographs are taken from
some of my own mounts in styrax. Of course I am aware that
this valve was very ably and fully treated recently elsewhere by
Dr. Butcher (Journ. R. M. S. 1911, p. 722), but my chief object
in bringing it before you now is to determine, if we can, which is
the correct image, the black dot or the white dot. [Here Mr.
O'Donohoe illustrated his remarks by photographs projected on
the screen.] The black- and white-dot images now thrown on the
screen have been taken direct at a magnification of 4,000
diameters, and to my mind it seems perfectly obvious that two
images so utterly unlike one another cannot both be correct

158 T. a. o'donohoe on the minute

representations of the same structure. The next two slides show
the inner membrane projecting beyond the outer one, and on
examining the edge of the fracture it becomes at once evident
that what is called the eye-spot is a comparatively large
perforation. This membrane also shows considerable thickness.
I have been able to find a small fragment in which the outer
membrane projects a little beyond the inner layer. This is seen
by the fact that the silex of the projecting part appears white.
It should now be noted that this white silex is sharply defined at
the edge, that this edge shows hardly any thickness, and that the
perforations are represented by black dots. The next image has
been obtained by making no other alteration than that of raising
the objective until the white dots appeared. On examining this
image we find the white silex has become black, and the edge of
the fracture which was so well defined in the black-dot picture is
now so blurred and fogged as to have become invisible. We have
next two fragments of Pleurosigma angulatum in juxtaposition,
showing respectively the black and white dots. The black dot
image gives the "postage-stamp" fracture well defined in white
silex, whereas the broken edge in the other fragment is black,
out of focus and blurred. We are therefore justified, I think,
in relegating the white-dot images of diatom structure to the
abode of Mr. Nelson's ghosts. Here, methinks, I hear the tyro
in microscopy cry out, " If that be so, why do we meet with
so many white-dot images in the books which are written for
our guidance ? " I prefer to let the writers of these books
answer for themselves. Mr. Pringle, in Practical Photomicro-
graphy, 1890, page 173, writes: "In spite of all these details,
A. pellucida is child's play to photograph in comparison with
such tests as Pleurosigma angulatum, Surirella gemma and
Navicula rhomboides by axial light and to show ' black dots.
Pleurosigma angulatum in white areoles, or Navicula rhomboides
in squares, with a special disc in the condenser, is infinitely
easier than the same in black dots."

Let us turn now to Plates III. and IV. of Dr. Spitta's Photo-
micrography (1899). What do we find? White-dot images of
all his diatomic tests. Not one black-dot image ! He has, no
doubt, some good reason for this, and turning to page 138 we
find it. Writing about the photography of Pleurosigma
angulatum, Dr. Spitta says : " It has two principal planes of
focus, and much difference of opinion exists as to which is the
correct one. The last picture taken by Dr. Van Heurck with

STRUCTURE OF COSCINODISCUS ASTEROMPHALUS, ETC. 159

the new Zeiss N.A. 1*6 objective, and the attendant para-
phernalia, seems to show that after all the black dot is more
^correct than the white one. As before stated, the white one
is the easiest to photograph, for the black dot seems never to
be sufficiently defined to look as sharp as we should like it."

For the sake of the aforesaid tyro I will here quote a little
advice which Mr. Nelson gave me eight years ago (I began
photomicrography very late in life) on the white dot. Among
several black-dot photographs which I sent him, and which he
was kind enough to praise, there was a white-dot Isthmia
nervosa of which he said : ' : I think the Isthmia would be better
with black-dot focus ; this white-dot focus is an out-of -focus
ghost. It is much easier to get than a correct picture, and on
that account it seems to be a favourite with some photo-
graphers ; but any one really interested in the work should aim
At something higher. Of course, with very fine structures, a
white dot is all that can be obtained with our present lenses."
I thought then, and still think, that this was the kind of
mentor who would always command and receive the highest
respect.

We come now to Pleurosigma angulatum, of which a black-dot
image x 3,700 is thrown on the screen. The next picture on the
screen shows a fractured valve which has been denuded of a part
of its outer membrane. The next image shows this outer mem-
brane x 2,000 broken up into fragments so minute that the
particles of silex have in some instances only one, two, three or
four holes shown as black round dots ; this outer membrane is so
thin that the silex is almost invisible, and in this respect differs
very much from the inner membrane, whose image x 2,000 is
now thrown on the screen. I do not, however, discern any
difference between the holes in the two membranes.

Finally, we have to consider the structure of Pleurosigma
balticum. This, because of its convexity and thickness, is difficult
to photograph, and yet more difficult to understand. I am
illustrating its structure by showing you fifteen different photo-
graphs, each of which I must describe very briefly ; but before
doing so, let me define the word " fibril " : a fine filament of silex
which contains holes in a row like a string of beads ; it may
be long or short. This definition differs altogether from that
which Mr. T. F. Smith gives to the same word.

The first slide shows the ordinary valve with Van Heurck's
canaliculi x 1,500.

160 T. A. O'DONOHOE ON COSCINOD1SCUS ASTEROMPHALUS, ETC.

The second slide shows the round black clots of the inner
membrane near the nodule, where the outer membrane has been
rubbed off (PI. 14, fig. 1). The third slide shows an impression
of the greater part of a valve caused by the adhesion of the outer
membrane to the slip.

The fourth slide shows a similar adhesion to the cover-glass,
as well as the valve from which the outer membrane was torn.
The fifth shows the same x 1,000.

The sixth slide shows fine hair-like bent fibrils breaking away
from the valve.

The seventh shows a part of the same valve x 2,000, on which
four fibrils of the inner membrane are visible.

The eighth is an image which puzzled me, and Mr. Nelson
kindly explained it thus : " This shows an upper bar crossing a
hole. It also shows the transverse girder work wonderfully
clearly" (PI. 14, fig. 2). The ninth slide shows the structure of
the inner membrane to be similar to the last, but this and the
three next following photographs were taken from Mr. Nelson's
slide.

The tenth shows the outer membrane breaking up into fibrils,
and sometimes even into isolated clots (PI. 14, fig. 3).

The eleventh and twelfth show continuations of the tenth.
The thirteenth shows the structure of the fibrils very well (PI. 14,
fig. 4). The fourteenth and fifteenth show the kind of structure
which is incorrectly taken for squares, but a glance at one of
the single fibrils causes the optical illusion to vanish.

In Pleurosigma balticum the fibrils run parallel with the raphe,
whereas in Pleurosigma angtdatum they seem to run obliquely to
the raphe, and this, it seems to me, is the chief difference in the
minute structure of the two valves.

Description of Plate 14.

Fig. 1. P. balticum, X 1,750. Showing the structure of the
inner membrane when the outer has been rubbed off.

,, 2. P. balticum, x 2,000. Inner membrane, showing the
holes crossed by very fine bars of silex.

3. P. balticum, x 2,000. Fibrils, photographed from Mr.
Nelson's slide.

,, 4. P. balticum, x 1,250. Fibrils.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 73, November 1912.

Journ. Q.M.C.

Ser. 2, Vol. XII , PI. 14

1

ill

ll III

will

I

.Hi!

!

Pliilli

.:

I

it:

!!i

t

III*

Fig. 1.

Fig. 3.

Fig-.

Fig. 2.
Photomicrogr. T. A. OD.

Structure of Pleurosigma balticum.

1G1

LAGENAE OF THE SOUTH-WEST PACIFIC OCEAN..

(SUPPLEMENTARY PAPER.)
By Henry Sidebottom.

{Read June 24/7/, 1913.)
Plates 15-18.

INTRODUCTION.

The Lagenae dealt with in this supplementary paper were-
arranged by the late Mr. Thornhill on nine slides, each of which
is divided into one hundred squares. Nearly every square is
occupied, with the exception of some on the last slide. The
number of specimens exceeds twelve thousand. In the material
for mv first paper the number of specimens of Lagenae exceeded
six thousand, thus making a grand total of over eighteen thousand.
For reasons stated in my former Introduction, it has not always
been possible to give the locality at which specimens were found.

The series dealt with now is on three sets of slides, Nos. 1-4 A
being Penguin gatherings, Nos. 1-3 b Penguin and Dart gatherings
combined and Nos. 1,2 c those on which Mr. Thornhill had just
begun to bring together specimens arranged according to a system
he had hoped to carry out.

The specimens of Lagenae on the three sets of slides were not
arranged in sequence with each other, so that the work has
proved more laborious than that of my first report.

The division of the keel, which occurs in a good many tests
and in more than one species, adds to the difficulty of identifica-
tion, and it is easy to be misled by it. The same may be said
of some of the markings on the faces of the test, which have
hitherto been considered as specific characters.

Again I must acknowledge the kindness of Mr. Millett, whose
advice I have always found most valuable and freely given. My
thanks are due to Mr. Wright, of Belfast, to Prof. Hickson,
of the University of Manchester, for kind assistance, and also
to Mr. Earland for bringing these papers before the Quekett
Microscopical Club and examining specimens for me in order to-

162 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

find out the nature of certain markings. Lastly, as regards the
text, I wish to acknowledge my indebtedness to my wife for her
assistance in rendering my descriptions more concise.

H.M.S. " Penguin." S.W. Pacific. 1897.

No.

Statioi

1.

939.

2.

940.

3.

941.

4.

943.

5.

945.

6.

947.

7.

949.

8.

952.

9.

954.

10.

955.

11.

956.

23.

f 2]
U7i

Lat. & Long.

f 18-29' S.
\ 178-38' E.
/ 18-57' S.
U 79-04'
/ 18-43'

U 78-51'
/ 19-21'
(.179-30'

21-47'
179-25'
/ 22-49'
\ 179-20'
/ 23-44'
\ 179-09'
/ 25-52'
\ 178-47' E.

f 26-57' 8.
1 178-35'

f 27-46'
\ 178-29'

/ 29-17'
i 177-17'

E.

8.
E.

S.
E.

S.
E.

S.
E.

S.
E.

S.

E.

S.
E.

8.
E.

H.M.S. "Pen

No. Station.

4.

24.

12.

18.

21.

24.

25.

27.

Lat.

r 33-

\157-

r 33-

\158-
/ 33-

U60-

f 33-
\161-

/ 33-

\162-

f 33
(163

/ 33-
V163-

f 33-
U64

/ 33-
\164

f 34

\165-

& Long.

53' S.

29' E.

50' 8.

47' E.

48' 8.

2' E.

56' S.

13' E.

56' 7"

S

33'

E

56' 6"

S

20'

E

57' 8.

56' E.

58' S.

37' E.

58' 5"

S

55'

E

0' 6"

S

37'

E

GUIN.

Fms.

2,578.
2,338.
1.190.

98S.

498.

575.

603.
1,073.
1,653.
1.676.

Fms.

No.

1,122.

12.

1,092.

13.

1,360.

14.

1,420.

15.

2,043.

16.

1,948.

17.

1,903.

18.

2,183.

19.

2,318.

20.

1,803.

21.

2,050.

22.

Station.
959.

961.

964.

974.

975.

976.

986.

987.

996.

998.

1,003.

Lat. & Long.

f 31-39' S.
\ 176-49' E.

/ 33-00' 8.

\176-16' E.

/ 34-52' 8.

(175-34' E.

f 35-01' S.
\171-37' E.

f 35-23' S.
1 170-34' E.
/ 36-09' S.

^ 169-20' E.

f 36-30' S.
\168-11' E.

f 37-10' S.
1 166-30' E.

/ 37-47' S.
\ 164-40' E.

f 38-24' S.

1 163-15' E.

/ 4305' 8.

(148-39' E.

S.W. Pacific. 1898.

No.

25. 1

Station.
35.

41.

44.

75.

26.

I

27.

28.

83.
85.
86.
87.

Lat. & Long.

/ 34-19' 8.

\168-6' E.

/ 34-20' S.

\ 168-28' E.

/ 34-22' 8.

\17019' E.

f 36-21' 8.

\176-44' E.

f 36-3' S.

\ 17855' E.

/ 34-33' S.

\. 178-15' W.

f 32-56' S.
\ 176-49' W.

S.

w.

/ 31-28' S.
{ 171-5' W.

/ 3216'
\175-54'

Fms.
2,210.

2,086.

917.

796.

994.
1,298.
1,207.

822.

735.
2,182.
1,611.

Fms.

828.

1,191.
979.

832.
1,389.

4,278.

3,360.
3,220.
3,100.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 163

No"

Station

29.

93.

90.

^in

94.

ou.-

95.

96.

31.

98.

32.

143.

No.

37.

38.

39.

40.

Station.
140.

70.

181.

182.

188.

191.

192.

393.

429.

480.

Lat. & Long.

Fins.

f 26-38' s.
\17417' W.

2,420.

f 2917' S.
\ 175-11' W.

3,105.

/ 25-53' S.
U"46' W.

2,775.

f 23-24' S.
\ 173-40' W.

3,205.

f 22-14' S.
1 17329' W.

3,420.

/ 21-8' S.
\ 174-7' W.

2,115.

f 23-15' 8.
\175-32' E.

2,351.
1

H.M.S. "

Penguin

Lat. & Long.

Fms.

f 10-57' S.
\162-21' E.

508.

f 23-17' 8.
\ 154-33' E.

470.

/ 11-42' 8.
U75-51' W.

2,335.

f 11-09' 8.
\ 175 -36' W.

1,992.

f 9-41' S.
\ 174-37' W.

2,290.

/ 8-57' 8.
V 174-03' W.

2,606.

f 8-36' S.
\ 173-51' W.

2,712.

/ 3-51' N.
\ 164-13' W.

2,330.

/ 4-55' N.
\ 160-54' W.

1,701.

/ 5-10' N.
\ 160-15' W.

2,033.

No. Station.

f

33.

34.

35.

36.

14S.

149.

151.

156.

157.

167.

169.

172.

Lat. <fc Long.

f 261' 8.

\ 172-56' E.

f 26-38' 8.

\172-26' E.

/ 27-55' 8.

\171-22' E.

f 29-35' 8.

\ 168-51' E.

f 29-42' 8.
\ 168-51'
/ 30-29'
\ 166-16'

f 30-57'
\ 160-52'

T 31-18'
\ 163-46'

E.

8.
E.
8.
E.
8.
E.

S.W. Pacific.

No.

40.

41.x

Station.
482.

487.

488.

498.

499.
502.
503.
505.
506.

Lat. & Long.

/ 6-15' N.
\ 160-36' W.

/ 7-25' N.
\ 160-59' W.

f 7-47' N.
\ 160-45' W.

/ 8-47' X.
\ 159-45' W.

f 904' N.
\ 159-32' W.

/ 9-43' N.
\ 159-07' W.

f 1004' N.
1 158-53' W.

f 10-43' N.
\ 158-30' W.

/ 11-01' N.
X 158-21' W.

Fms.
2,428.

2,070.

1,632.

1,269.

1,446.

1,819.

1,557.

1,010.

Fms.

1,861.
2,501.
2,573.
2,588.

2,579.
2,758.

2,800.
2,938.
2,863.

Ko. Station.

f

No date

42.

Lat. k. Long.

2415' 8.
E.

S.
E.

/ 24-36' 8.
\15332' E.

/ 24- 1
\153-1
/ 24-34'
\ 153-32'

H.M.S. "Dart."

Fms.
328.

478.

392.

No. Station. Lat. <fc Long.

Fms

d , / 19. f 29-22' S.
^\(14.5.97.)\153-51' E.

465

44.{(16.1.97.){ 1 ^;

481

164 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Family LAGENIDAE.

Sub-family Lageninae.

Lagena Walker and Boys.

Lagena globosa Montagu sp. (PI. 15, figs. 1-3).

Serpula (Lagena) laevis globosa Walker and Boys, 1784, Test. Min. r

p. 3, pi. 1, fig. 8.
Vermiculum globosam Montagu, 1803, Test. Brit., p. 523.

Very numerous and of varying size and shape. The orifice
and internal tube are subject to great variation. Locality :
Many .stations.

PL 15, fig. 1. The orifice is small and somewhat hooded, and
the test often inclined to be apiculate. Locality : Many stations.
Rare.

PI. 15, fig. 2. An elongate variety. Locality: Uncertain.

Only one found.

PI. 15, fig. 3. An interesting variation, the body of the test
being partly clear and partly opaque. The curiously produced,,
flattened mouth, which appears to be divided or pinched in at the
centre, points to its being allied to the one figured + PI. 14, fig. 2.*
The entosolenian tube is absent. t Locality : Nos. 21-26, 34, 38,
42, 44.

+ P1. 14, fig. 2. Locality: Uncertain.

+ P1. 14, fig. 4. The slightly elongated form predominates.
Locality : Many stations, including Nos. 6, 8 ; after No. 22 only
at one or two stations.

+ P1. 14, fig. 5. This compressed variety of the above is found
sparingly at a few stations, but tests that are much more com-
pressed, and pointed towards the aperture, are frequent.

Lagena globosa Montagu sp. single and bilocular form.

Lagena globosa Montagu sp. single and bilocular form, Sidebottom,
1912, Journ. Q. M. C, p. 380, pi. 14, figs. 7, 8, 9.

Locality : Many stations up to No. 19, also at Nos. 33, 43, 44.

* The "4*" denotes that the reference is to " Lagenae of the South-
West Pacific Ocean " (Journal Quekttt Microscopical Club, 1912, ser. 2,
vol. xi., pp. 375-434, pis. 14-21).

f The numbers throughout this paper refer to my charts on pp. 162, 163,
where will be found the official numbers of the stations, with other
particulars.

HENRY SIDEBOTTOM OX LAGENAE OF THE SOUTH-WEST PACIFIC. 165

Lagena globosa Montagu sp. var. maculata Sidebottom.

Lagena globosa Montagu sp. var. maculata, Sidebottom, 1912,
Journ. Q.M.C. p. 380, pi. 14, figs. 10, 11.

Locality : Nos. 5 9.

Lagena globosa Montagu sp. var. emaciata Reuss.

Lagena emaciata Reuss, 1862 (1863), p. 319, pi. 1, fig. 9.
Lagena globosa Montagu sp. var. emaciata (Reuss) Sidebottom,
1912, Journ. Q. M. G. p. 381, pi. 14, figs. 13-15.

Locality : Present at numerous stations throughout the series.

Lagena apiculata Reuss sp. (PI. 15, fig. 4).

Oolina apiculata Reuss, 1851, p. 22, pi. 1, fig. 1.
Lagena apiculata Reuss, 1862 (1863), p. 318, pi. 1, figs. 1, 4-8,
10, 11.

PI. 15, fig. 4. A large, solitary specimen. Locality : No. 15.

+ P1. 14, fig. 16. Always rare. Locality : At Nos. 24, 43, and
a, few other stations.

"J" PI. 14, figs. 17, 18. Found at many stations. Locality:
Chiefly at Nos. 2, 24, 42, 44.

*P1. 14, figs. 19, 20. The tube in this variation is very
delicate, and often lies broken inside the test. Locality: Occurs
at very many stations.

Lagena apiculata Reuss sp. var. punctulata Sidebottom.

Lagena apiculata Reuss sp. var. punctulata Sidebottom, 1912,
Journ. Q.M. C, p. 382, pi. 14, figs. 21-23.

Locality : Nos. 3, 5-11, 41, 43.

Lagena longispina Brady (PI. 15, figs. 5, 6).

Lagena long ispina Brady, 1881, Quart. Journ. Micro. Sci., vol. xxi.,

N.S., p. 61.
Lagena longispina Brady, 1884, p. 454, pi. 56, figs. 33, 36 ; pi. 59,

figs. 13, 14.

As Brady states in the Challenger Report, this is simply a
variety of L. globosa. It is not unusual for L. globosa to have
the base of the test roughened or finely spinous. The larger of

166 HENRY S1DEB0TT0M ON LAGENAE OF THE SOUTH-WEST FACIFICL

the two specimens figured is so opaque that it is impossible to
say whether the entosolenian tube is present. Locality : Nos. 5,,
7, 9, 39-41, 44.

Lagena ovum Ehrenberg sp.

Miliola ovum Ehrenberg, 1843, p. 166; 1854, pi. 23, fig. 2;
pi. 27, fig. 1 ; pi. 29, fig. 45.

Locality : This unsatisfactory form occurs at many stations,
but is always rare. See remarks +p. 382.

Lagena botelliformis Brady (PL 15, figs. 7, 8).
Lagena botelliformis Brady, 1884, p. 454, pi. 56, tig. 6.

PI. 15, fig. 7. Only two specimens found. The orifice is phia-
line, and there is a short internal tube. Locality : No. 44.

PL 15, fig. 8. This is a very fine example in the apiculate-
condition. See also +PL 14, fig. 24. Locality: No. 12.

+ P1. 14, figs. 24, 25. Locality; Many stations.

**"PL 14, figs. 26-28. Locality: Stations uncertain.

Lagena laevis Montagu sp. (PL 15, figs. 9, 10).

Serpula (Lagena) laevis ovalis Walker and Boys, 1784, p. 3, pi. 1,.

fig. 9.
Lagena laevis (Walker and Jacob) Williamson, 1848, p. 12, pi. 1,

figs. 1, 2.

L, laevis occurs frequently in these gatherings, and the form
of the test, the decoration of the neck and the position of the-
internal tube varies. Some are apiculate. In a few instances
there is an entosolenian tube situated at the base. Locality .-
Many stations.

PL 15, fig. 9. The tests are semi-opaque, the short neck is-
decorated and the internal tube straight. In several instances
fine spines project at the base. Locality : Nos. 1, 2, 3, and one-
or two others.

PL 15, fig. 10. This appears to be a smaller variety of the-
above. The tests are too opaque for me to make out whether
the entosolenian tube is present. Some are apiculate and may-
be L. laevis var. distoma Silvestri. Locality : At a good many
stations throughout the series.

HENRY SIDEBOTTOM ON LAGEXAE OF THE SOUTH-WEST PACIFIC. 167

Lagena laevis Montagu sp. var. distoma Silvestri.

Lagena laevis (Montagu) Silvestri, 1900, p. 244, pi. 6, figs. 74, 75.

Examples are rare, but they occur at a fair number of stations..
Locality : Chiefly at Nos. 1, 6, 11, 15, 17, 22, 42-44. .

Lagena gracillima Seguenza sp.

Amphorina gracilis Costa, 1856, p. 121, p. 11, fig. 11.
Am ph or ina gracillima Seguenza, 1862, p. 51, pi. 1, fig. 37.

Eight specimens occur which are all curved. Locality : No. 44.
Besides these specimens, only two or three others were found.
Locality : Uncertain.

Lagena elongata Ehrenberg sp.
Miliola elongata Ehrenberg, 1854, pi. 25, 1a, fig. 1.

I do not think these can be separated from L. gracillima
Seguenza sp., as they appear to pass insensibly from one form to
the other. Seven specimens occur, also two or three doubtful
examples. Locality : Six at No. 43, and one at No. 2.

Lagena aspera Keuss (PI. 15, figs. 11-13).
Lagena aspera Eeuss, 1861, p. 305, pi. 1, fig. 5.

Pi. 15, fig. 11. This is in good condition, except that the neck
is broken. The protuberances, which are arranged in lines, are,
I think, tubular. Locality : No. 17.

On another square are two smaller specimens, with very small
protuberances ; these also have the neck fractured. They appear
to be a weak form of the above. Locality : Uncertain.

PI. 15, g. 12. Two specimens only occur ; the one figured is in
a very opaque condition, the other is clear but much smaller.
Locality : Nos. 1, 22.

PI. 15, fig. 13. Three specimens found, the neck being bent to
one side in each case. It is not unlikely that future investigation
will reveal a connection between these forms and L. striatopunctata.
Locality : No. 43.

There are also two oval tests, which have the protuberances,
and the lines in which they are arranged, farther apart. The
protuberances are very minute. Locality : No. 10.

168 HENRY S1DEB0TT0M ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Lagena rudis Reuss (PI. 15, fig. 14).

Lagena rudis Reuss, 1862 (1863), vol. 46, p. 336, pi. 6, fig. 82.

A single example. The test is opaque and of a faint silvery-
yellow colour. Locality : No. 24.

Lagena ampulla-distoma Rymer Jones.

Lagena vulgaris var. ampulla-distoma Rymer Jones, 1872, p. 63,
pi. 19, fig. 52. See also + p. 384.

Locality : Nos. 1, 2, 3, 8, 19, 22, 24, 42, 43.

Mr. Millett, 1901, p. 6, mentions two other localities for this
species, besides the Malay Archipelago ; it may therefore be worth
while to state that I have since recorded it from the coast of
Delos and Palermo.

Lagena hispida Reuss (PI. 15, fig. 15).

Sphaerulae hispidae Soldani, 1798, p. 53, pi. 17, v, x.

Lagena hispida Reuss, 1858, p. 434.

Lagena hispida Reuss, 1862 (1863), p. 335, pi. 6, figs. 77-79.

In one form or another this is found at nearly all the stations.
There is great variation in size, and shape of the tests, and many
of the small ones have a long entosolenian tube at the opposite
end from the neck, so that it is difficult in some cases to say which
is the right end up. If turned one way, they might be treated as
apiculate forms.

PI. 15, fig. 15. The orifice is circular and sunk in a depression.
The oral end of the test is surrounded by a series of short spines.
A solitary example. Locality : No. 24.

* PI. 15, fig. 1. Ten specimens occur. Locality : Nos. 5, 6, 8,
and a single example at either Nos. 41 or 42.

Lagena hispida Reuss, compressed form.

+ P1. 15, fig. 2. Locality: Nos. 1-3, 5-7, 10, 24, 33, 34, 36,
38 40, 42.

Lagena hispida Reuss var. tubulata Sidebottom (PI. 15, fig. 16).

Lagena hispida Reuss var. tubulata Sidebottom, 1912, Joum.
Q. M. C, p. 385, pi. 15, figs. 3-5.

PI. 15, fig. 16. Nearly all the smaller tests have their necks
broken, and a few are very large, as can be judged from the

HENRY SIDEBOTTOM OX LAGENAE OF THE SOUTH-WEST PACIFIC. 169

drawing. The largest specimens have the body much clogged by
exogenous shell-growth, or debris, through which small spines
often project. Locality : Nos. 17, 19. 24. 25, 35. 36. Always rare.
+ P1. 15, fig. 5. This variation, which is much more delicate in
every way. is found at many stations. Locality: Xos. 1-11. 24,
25. 33, 35, 36. 39.

Lagena striata d'Orbigny sp. (PL 15. fig. 17).
Oolina striata d'Orbigny, 1839, p. 21, pi. 5, fig. 12.

Many examples at numerous stations. They vary remarkably
both in size and decoration. Many are apiculate. -f- See remark-.
p. 386.

PI. 15. fig. 17. In this, the fine costae project at the base. The
neck is bent to one side, the body of the test is also slightly
curved. On a square by themselves are fifteen tests which have
the contour of L. clavata, with the point at which the test begins
to narrow towards the base sharply angular. Only two are
marked on the chart. Locality : Nos. 1, 3-5. 7. 8. 12. 17. 21, 24,
34. 39. 40.

Lagena (Amphorina) Lyellii Seguenza sp. is found frequently.
This form may be treated either as L. striata, or L. sulcata in an
apiculate condition.

* PI. 15. fig. 6. Twenty-three specimens are on the slide.
Locality : Nos. 2. 3. 4.

* PI. 15, fig. 8. Fourteen fine examples occur, and a number
of smaller ones. Taking the whole series into account they pass
gradually into L. Lyellii Seguenza. Locality; Nos : 2-12. 15, 17.
21, 24, 29, 31, 33, 34. 39. 40, 42, 43.

+ EL 15, fig. 9. Five typical tests are on the slide, but they
are mixed with others that are not typical, and so the exact
locality cannot be given with certainty. They were found, how-
ever, at one or two of the following stations. Locality : ZSTos.
1, 5, 11, 13.

On another slide two examples are placed. Locality : 2Sos.
23. 24.

Lagena striata d'Orbigny sp. var. tortilis Egger.

Lagena tortilis Egger, 1893, p. 329, pi. 10, figs. 61-63.

Two examples only. Locality : Nos. 43. 44.

Journ. Q. M. C., Series II. No. 73. 12

170 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC

Lagena striata d'Orbigny sp. var. striatotubulata Sidebottom.

Lagena striata d'Orbigny sp. var. striatotubulata Sidebottom,.
1912, Journ. Q. M. C., p. 387, pi. 15, figs. 11, 12.

This is well represented. A good many are more or less-
fractured, otherwise they are clean and fresh-looking. Locality r
Nos. 4-12, 23, 24, 29, 33, 34, 39, 40.

Lagena distoma Parker and Jones.

Lagena laevis var. striata Parker and Jones, 1857, p. 27S, pi. 11,
fig. 24.

There is a single large specimen and it agrees with the
Challenger figure, pi. 58, fig. 11. Locality : No. 2.

There are about twelve examples which have their sides slightly"
curved and parallel as in the type. Locality : Uncertain.

Lagena lineata Williamson sp.

Entosolenia lineata Williamson, 1848, p. 18, pi. 2, fig. 18.

Many examples found. Locality : Nos. 1, 2, 4, 5, 9, 10, 13-15,
17-20, 22, 24, 25, 36, 38, 42-44.

+ PI. 15, fig. 15. The variety with the costae curved occurs at
many stations.

Non-apiculate forms also are present.

Lagena variata Brady.

Lagena variata Brady, 1881, Quart. Journ. Micr. Sci., vol. 21,.

N.S., p. 61.
Lagena variata Brady, 1884, p. 461, pi. 61, fig. 1.

Only two typical examples. Locality : Uncertain.

+ PL 15, fig. 13. The neck of the test is in many cases not so
long as in the figure referred to. Locality : Nos. 14, 15, 17, 19,
22, 24, 25, 44.

Lagena costata Williamson sp. (PI. 15, figs. 18, 19).

Entosolenia costata Williamson, 1858, p. 9, pi. 1, fig. 18.

Occurs frequently, typical and otherwise, sometimes apiculate.
PL 15, fig. 18. This appears to be an elongate form with from.

HENRY SIDEBOTTOiM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 171

eight to ten costae. Entosolenian tube straight. Locality :
Ud certain ; probably No. 22 and a few other stations.

PI. 15, fig. 19. These appear to be the same, but they have
only six costae, and occur more frequently. .Nos. 15, 17-20, 23,
24, 29, 33-36.

+ P1. 15, fig. 16. Locality: Many stations throughout the
whole series.

+ P1. 15, fig. 19. Locality: No. 43.

Lagena acuticosta Reuss (PI. 15, fig. 20).
Lagena acuticosta Reuss, 1861, p. 305, pi. 1, fig. 4.

An unsatisfactory species, for it is linked closely with L. costata
on the one hand, and L. sulcata on the other. Locality: Many
stations up to No. 22 ; afterwards extremely rare.

PI. 15, fig. 20. An odd specimen, probably a very weak form.
Locality : Uncertain.

+ PI. 15, fig. 22. Tests similar or nearly so oc^ur, but they are
not so large. Locality : Nos. 2, 7, and a few other stations.

Lagena melo d'Orbigny sp.
Oolina melo d'Orbigny, 1839, p. 20, pi. 5, fig. 9.

There are several fine typical examples and a few small ores
on the slide, but as they are mixed with other varieties the
locality cannot be determined.

The form with the cross-bars sunk, which is assigned by
Reuss to L. catenulata Williamson, 1862 (1833), pi. 6, fig. 75, is
also present.

Lagena hexagona Williamson sp. (PI. 15, figs. 21-23).

Entosolenia squamosa var. hexagona Williamson, 1848, p. 20, pi. 2,
fig. 23.

Very many beautiful specimens occur ; some are globular,
others pyriform, with and without necks. The depth and size of
the mesh var} 7 greatly.

A few, w^hich I take to be L. geomeirica Reuss, 1862 (1863),
pi. 5, fig. 74, are exquisite, although the arrangement of their
cells is not always parallel. The cells are deep, and their sides
exceedingly delicate. Several have short necks. I have not
attempted to draw them, as I could not have produced the

172 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

desired effect. Locality: Again the mixing of the varieties
prevents me from giving any definite information.

There are a few which appear to be the same as the one
figured by Brady in the Challenger Report, pi. 58, fig. 33, of
which the angles of the cells tend to become spinous, especially
at the base of the test. This peculiarity seems to be feebly indi-
cated in Brady's figure.

PI. 15, fig. 21. Several of this elegant form occur. Locality :
Uncertain.

PI. 15, fig. 22. A globular variety.

PI. 15, fig. 23. A compressed variation of the above, but of
smaller size. These two forms are placed together on the slide.
Locality ; Taking the two forms together they are marked
Nob. 2-5, 13, 17-20, 44.

Lagena squamosa Montagu sp.

Vermiculum sqtiamosum Montagu, 1803, Test. Brit. p. 526, pi. 14,
%. 2.

A few only are present. Locality : Uncertain.

Lagena exsculpta Brady.

Lagenulina sulcata Terquem, 1876, Anim. sur la Plage de

Dunkerque, fasc. 2, p. 68, pi. 7, fig. 9.
Lagena exsculpta Brady, Quart. Journ. Micr. Sri., vol. xxi., N.S.,

p. 61.
Lagena exsculpta Brady, 1884, p. 467, pi. 58, fig. 1 ; pi. 61, fig. 5.

Five examples found, and they are compressed. Three of them
are in poor condition. These latter are not quite typical, as
the sculptui e becomes irregular at the base. Locality : ISTos.
37, 39.

Lagena sulcata Walker and Jacob sp. (PI. 15, figs. 24, 25).

Serpula (Lagena) striata sulcata rotunda Walker and Boys, 1784,

p. 2, pi. 1, fig. 6.
Serpula (Lagena) sulcata Walker and Jacob, 1798, p. 634, pi. 14,

fig. 5.

This common foraminifer is well represented. In some the
body of the test is globular, and in others cylindrical. Apicu-

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 173

late forms also occur. Locality : Nos. 4, 14, 15, 20, 24, 26, 38,
42-44, and a few others.

PI. 15, fig. 24. This is closely allied to L. alifera Beuss, 1870,
p 467. Von Schlicht, 1870, pi. 3, figs. 15, 16, 21, 22. Locality :
Nos. 3. 10, and two or three others.

PI. 15, fig. 25. This form, known as L. sulcata var. interrupta
Williamson, is hardly worthy of a varietal name, as it is not at
all uncommon for some of the costae or striae, both in L. sulcata
and L. striata, to be shorter than the others.

Lagena plumigera Brady (PI. 15, fig. 26).

Lagena plumigera Brady, 1881, Quart. Journ. Jficr. Sci., vol. 21,

N.S., p. 62.
Lagena plumigera Brady, 1884, p. 465, pi. 58, figs. 25, 27.

Two of the tests are similar to the one figured ; several others
are smaller and much damaged. Locality : Nos. 1, 2, 43.

Lagena semilineata Wright (PI. 15, fig. 27).

Lagena semilineata Wright, 1884-5, App. 9, 1886, p. 320, pl. 26,
fig. 7.

Evidently a bold form of L. semilineata. Locality: Three
examples at Station No. 2.

Lagena gracilis Williamson.

Lagena gracilis Williamson, 1848, p. 13, pl. 1, fig. 5..

This protean species is found at many stations throughout
the whole series. All the forms represented in the Challenger
Report, 1884, appear to be present. No line of demarcation can
be drawn between this species and apiculate forms of L. sulcata
and Z. striata ; they are also linked with L. distoma Parker and
Jones.

Lagena quinquelatera Brady.

Lagena quinquelatera Brady, 1881, Quart. Journ. Micr. Sci., vol.

21, N.S., p. 60.
Lagena quinquelatera Brady, 1884, p. 484, pl. 61, figs. 15, 16.

I take this to be a variety of L. gracilis.
Two specimens only. Locality : No. 2.

174 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Lagena semistriata Williamson.

Lagena striata var. /? semistriata Williamson, 1848, p. 14, pi. 1,
figs. 9, 10.

The great majority are small. Some have the neck bent to
one side and the body slightly curved. A few are cylindrical and
others have the contour of L. clavata d'Orbigny. Locality : Nos.
1, 20-22, 29, 42-44.

Lagena crenata Parker and Jones var. (PI. 15, fig. 28).

Lagena crenata Parker and Jones, 1865, p. 420, pi. 18, fig. 4.

They are not typical, but I think they are best placed under
the above heading. The projecting parts at the base run partly
towards its centre as blades. The neck is not decorated. A few
of the examples are not so slim as the one figured, and have their
sides slightly convex. Thirteen specimens occur. I cannot give
all the stations at which they are found, but the following may
be indicated. Locality : 22, 43.

Lagena Thornhilli Sidebottom (PI. 15, fig. 29).

Lagena Thornhilli Sidebottom, 1912, Journ. Q.M.C., p. 390,
pi. 15, fig. 26.

They differ slightly from the one figured at the above reference,
for the upper parts of the wings are joined together so as to
form a hood, as shown in the figure. In one of the examples
the three cavities formed by the hood are blocked with exogenous
shell-growth.

Four examples occur. Locality : 6, 8, 29.

Lagena stelligera Brady.

Lagena stelligera Brady, 1881, Quart. Journ. J/icr. Sci., vol. 21,

N.S., p. 60.
Lagena stelligera Brady, 1884, p. 466, pi. 57, figs. 35, 36.

A good many agree with Brady's Challenger figure, pi. 57,
fig. 35, but some are more slender, and several are very
minute.

See remarks, + pp. 391, 392. Locality : Nos. 5, 14, 17-19, 21,

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 175

22, also Nos. 23, 24, 29, 32, 33, 35, 37, 39-41. From these latter
stations a few of the " nude " form were obtained.

* PL 16, fig. 1. In most of the specimens, some of the costae
-are more prominent than the others, but none of them are "inter-
rupted," as in the figure referred to. Locality : 10, 22-24, 36, 39.

+ P1. 16, fig. 2. Numerous examples of this " nude " variety
are on the slides, some having very long, delicate necks. The
apiculate portion varies both in width and length. Two very
large tests were found, and except for the absence of the costae
they agree well with the Challenger figure, pi. 57, fig. 36.
Locality : Nos. 2, 3, 5, 12, 19, 23, 24, 29, 32, 33, 35, 36, 38-40.

+ P1. 16, fig. 3. Locality: Nos. 3-7, 9, 10, 13, 17, 23, 24, 26,
29, 33 35, 39, 40.

* PI. 16, fig. 4. Compressed. Nine examples found. Locality:
Nos. 2, 24. Other stations uncertain.

Lagena stelligera Brady var. eccentrica Sidebottom (PI. 15,

fig. 30).

Lagena stelligera Brady var. eccentrica Sidebottom 1912, Journ.
Q. M. O., p. 392, pi. 16, figs. 5, 6.

PI. 15, fig. 30. On this specimen the ridge at the base is
scarcely perceptible. Two or three only found. Locality: Un-
certain.

+ PI. 16, fig. 5. Not typically represented in these gatherings.

+ P1. 16, fig. 6. The examples generally have the ridge at the
base carried farther up the side of the test. Locality : Nos. 11,
14, 37.

Lagena stelligera Brady var. eccentrica Sidebottom, com-
pressed form (PL 15, fig. 31).

This is the compressed form, and some of the specimens from
No. 43 are in fine condition. Locality : Nos. 10, 13. 14, 19, 20-
43. Very rare, except at No. 43.

Lagena striatopunctata Parker and Jones.

Lagena sulcata var. striatoptmctata Parker and Jones, 1865,
p. 350, pi. 13, figs. 25-27.

Various forms are present. Some have the neck bent to one
.side, others have only a very short neck. The body of the test

176 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

also varies greatly, being occasionally almost globular. Locality :
Nos. 1-3, 22, 24 26, 33, 34, 38, 42, 43.

Lagena striatopunctata Parker and Jones (?) var. complexa

Sidebottom.

Lagena striatopunctata Parker and Jones (?) var. complexa Side-
bottom, 1912, Journ. Q. M. C, p. 393, pi. 16, fig. 11.

"*" PL 16, fig. 11. None of the tests are in perfect condition,
all showing signs of the disintegration mentioned at the above
reference. Locality : Nos. 7, 9, 24.

Lagena striatopunctata Parker and Jones var. inaequalis

Sidebottom.

Lagena striatopunctata Parker and Jones var. inaequalis Side-
bottom, 1912, Journ. Q. J/. C, p. 393, pi. 16, fig. 12.

Three tests are on the slide, but only two belong to this variety.
Locality : Two of the following, Nos. 4, 10, 11.

Lagena striatopunctata Parker and Jones var. spiralis Brady.

Lagena spiralis Brady, 1884, p. 468, pi. 114, fig. 9.

Locality : Nos. 1-4, 22, 37, 38, 43, 44. Very rare except at
No. 1.

Lagena Fieldeniana Brady.

Lagena Fieldeniana Brady, 1878, Ann. Mag. Nat. Hist. (5) vol. 1.

p. 434, pi. 20, fig. 4.
Lagena Fieldeniana Brady, 1884, p. 469, pi. 58, figs. 38, 39.

A solitary, rather rotund example, of which the neck is broken
off short. Locality : Uncertain.

Lagena desmophora Rymer Jones.

Lagena vulgaris var. desmophora Bymer Jones, 1872, p. 54,
pi. 19, figs. 23, 24.

The specimens are typical and in good condition. All are, or
have been, apiculate. The number of spines at the bate varies
from one to four. Locality : Nos. 2, 5, 7-11, 13, 33, 40.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 177

Lagena foveolata Reuss.

Lagena foveolata Reuss, 1862 (1863), p. 332, pi. 5, fig. 65.
Lagena No. 25, von Schlicht, 1870, p. 10, pi. 3, fig. 25.

Three or four only occur. The sculpture of the test is ex-
ceedingly fine. Locality : No. 43, and one or two other stations
which are uncertain.

Lagena foveolata Eeuss var.

Lagena foveolata Reuss var. Sidebottom, 1912, Journ. Q. M. 0. r
p. 395, pi. 16, figs. 16, 17.

It is possible that further investigation may reveal this to be
an apiculate form of one of the variations of L. melo d'Orbigny
sp. Locality .- Nos. 1, 2, 4, 6, 8, 10, 12, 14, 15, 17, 19, 21, 22,
24, 33, 36, 38, 40, 42-44.

Lagena foveolata Reuss var. spinipes Sidebottom.

Lagena foveolata R,3uss var. spinipes Sidebottom, 1912, Journ.
Q. M. 67., p. 396, pi. 16, figs. 18-20.

The tests are not in the best condition, and in some instances
the spines appear to be absent, or scarcely perceptible. The
rotund form does not occur. Locality : Fifteen specimens at
at No. 2, three at No. 3, four at No. 4.

Lagena foveolata Reuss (?) var paradoxa Sidebottom (PI. 15,

fig. 32).

Lagena foveolata Reuss (?) var. paradoxa Sidebottom, 1912,
Journ. Q. M. C, p. 395, pi. 16, figs. 22, 23.

This is one of the commonest foraminifera in these gatherings.
The tests vary greatly in size and shape. Locality : Nos. 1-22,
(except No. 17), 23-26, 29, 31, 33, 34-36, 39-41, 44.

Lagena lamellata Sidebottom.

r

Lagena lamellata Sidebottom, 1912, Journ. Q. M. C, p. 396,
pi. 16, figs. 24, 25.

I can only identify four tests. Locality : Two occur at No. 43 i
the other station or stations are uncertain.

178 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Lagena Hertwigiana Brady (PI. 15, fig. 33).

Lagena Hertwigiana Brady, 1881, Quart. Journ. Micr. Sci., vol. 21,

N.S., p. 62.
Lagena Hertwigiana Brady, 1884, p. 470, pi. 58, fig. 36.

The figure in my copy of the Challenger Report, pi. 58,
fig. 36, does not show the reticulation referred to in the description
of the species in the text, p. 470. In the three or four specimens
found in these soundings, the surface is roughened and the
perforations show very plainly. Locality : Uncertain, with the
exception of No. 43.

Lagena Hertwigiana Brady var. undulata Sidebottom.

Lagena Hertwigiana Brady var. undulata Sidebottom, 1912,
Journ. Q. M. C, p. 397, pi. 16, figs. 26-28.

Many examples occur. Locality : Nearly all the stations, but
chiefly Nos. 2, 7, 10, 17, 24, 34, 43.

Lagena pacifica Sidebottom.

Xagena pacijica Sidebottom, 1912, Journ. Q. M. C, p. 398, pi. 16 f
fig. 29.

Only two or three specimens found. Locality : Uncertain.

Lagena splendida sp. nov. (PI. 16, fig?. 1-3).

I am quite at a loss how to describe this exquisite Lagena.
-adequately, and I am unable to draw it owing to the complexity
of its decoration, which is exceedingly minute. The test glistens
and most probably it has been apiculate. The neck is fractured.
There is a second specimen which I think is the same, but there
is a slight difference in its appearance which I am unable to
explain. It is apiculate. Locality : Uncertain.

Note. Not being able to get a satisfactory definition with my
microscope, I submitted the test to Mr. Earland for examination,
who had better means of lighting up the test than I had. His
observations were made with the assistance of a Zeiss vertical
illuminator and daylight instead of artificial light. He writes as
follows :

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 179

" The markings appear to be knife-edged costae, from one side
of which triangular processes project at intervals. The apex of
the process barely touches the inner side of the adjoining co^ta.
. . . The triangular processes are Hush with the costae at their
base, but apparently sink away towards the apex, which is
probably but little raised above the wall of the test. The sunken
parts between the processes have a matt surface, whereas the
processes and costae are quite translucent."

I may say that my own examination of the test agrees to a
great extent with the above, but I think the edges of the costae
are waved (see PI. 16, fig. 3).

In a second communication Mr. Earland writes : " I succeeded
in getting a stereoscopic view of the shell under a ^ in. yesterday,
and it gave rather a fresh view of its structure. It seemed to be
covered with lines of pyramidal points in broken lines. Each
pyramid is a blunt spine."

I have not succeeded, however, in seeing these characters of the
test.

The figure (PI. 16, fig. 2) gives the effect of what I think I see
under the microscope, and it coincides to a great extent with
Mr. Earland's first description, though the details given in his
second communication do not appear to me to be necessarily
contradictory. I wish to acknowledge my sense of the trouble
Mr. Earland has taken in the matter.

Lagena spumosa Millett (PI. 16, fig. 4).

Lagena spumosa Millett, 1901, p. 9, pi. 1, fig. 9.

Most of the tests are slightly curved at the oral end, but the
" bird's-clawlike " process is more slender than is indicated in
Mr. Millett's illustration. Several are more elongate than the
one figured. Locality . Frequent at No. 22 ; Nos. 24. 38, 40, 42,
43, and a few other stations.

Lagena spumosa Millett, var.

Lagena spumosa Millett var. Sidebottom, 1912, Journ. Q. 21. C,
p. 398, pi. 16, fig. 30.

It is curious that the aboral end of the test appears to have
teen slightly abraded, I think in all cases. Locality : Nos. 4, 6,
7, 10, 11^ 13, 24, 25, 33, 35, 39, 40, 42, 43.

180 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Lagena Chasteri Millett.
Lagena Chasteri Millett, 1901, p. 11, pi. 1, fig. 11.
See my remarks on the type-form + p. 398.

Lagena Chasteri Millett (var. ?).

Lagena Chasteri Millett (var. ?) Sidebottom. 1912, Journ..
Q.M.C., p. 398, pi. 1G, figs. 32-34.

Many occur, but I am quite unable to separate this variation
from the type, for the curious little " stopper " at the orifice is
never so pronounced as in Mr. Millett's figure, and is often
apparently absent. Taking the type-form and the variation to-
gether, for they are mixed on the slides, they occur as follows :
Locality ; Nos. 1-4, 22, 34, 38, and frequently at Nos. 42-44.

Lagena pannosa Millett var.

Lagena pannosa Mille;t var. 1901, p. 11, pi. 1, fig. 14.

It is probable that two or three examples of this variation are^
present. Locality : Uncertain.

Lagena intermedia Sidebottom.

Lagena intermedia Sidebottom, 1912, Journ. Q.M.C., p. 399,.
pi. 17, figs. 1-3.

Locality : Nos. 3, 11, 12, 23, 24, 29, 32, 39-41.

Lagena quadralata Brady.

Lagena quadralata Brady, 1881, Qua/rt. Journ. Micr. Sci., vol. xxL

(N.S.), p. 62.
Lagena quadralata Brady, 1884, p. 464, pi. 61, fig. 3.

In the Challenger Report Brady states that this Lagena is.
allied to the Lagena alifera of Reuss. I should prefer to con-
sider it as a variety of L. lagenoides Williamson var. tenuistriata
Bradv, for we know that this latter occurs in the trifacial
condition (see * PI. 19, fig. 5), and therefore it is not surprising
to find it with four equidistant keels ; also I have a good example
of Jj. lagenoides with five equidistant keels. The specimen found
is very small and not in the best condition. I think the wings
are tubular, but cannot be certain. On the same slide there-

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 181

are two examples with three keels, and two with five keels.
Locality : One specimen at No. 1. Other stations uncertain.

Note. One or two examples occur with four keels which are
not tubulated. These I should place as a variety of L. striata.

Lagena sp. in cert.

Lagena sp. incert. Sidebottom, 1912, Journ. Q. M. C, p. 399, pi. 17,
figs. 4, 5.

Locality : Three examples at No. 2, two at No. 24.

Lagena laevigata Reuss, sp. (PL 16, fig. 5).
Fissurina laevigata Reuss, 1850, p. 366, pi. 46, fig. 1.

Large and small examples of the type-form occur, but they are
not numerous. It is impossible to separate L. laevigata from
L. acuta, as the one passes insensibly into the other. Many other
examples are present in which the orifice is not central. Forms
ranging round Fissurina oblonga Reuss, 1862 (1863), pi. 7, fig. 89,
are frequent, and are found at many stations. A few specimens
occur that are circular in outline.

PI. 16, fig. 5. There are two sets of these and they vary a little.
Some have the appearance of being subcarinate, but this seems
to be caused by the test being clearer at its edge than at any other
part. Only two or three examples have the spines at the orifice
well developed, and most have a small wing at either side of the
neck. There is no internal tube. Locality : Nos. 42-44.

Note. These are not far removed from L. falcata Chaster,
1892, p. 6, pi. 1, fig. 7. On another square (locality uncertain)
there is one typical form, and there are also one or two others
that are carinate at the base, which seem to be intermediate
between L. falcata and Mr. Millett's figure of L. marginata var.
Millett, 1901, p. 497, pi. 8, fig. 21.

Lagena laevigata Reuss sp. var. virgulata Sidebottom (PI. 16,

fig. 6).

Lagena laevigata Reuss sp. var. virgulata Sidebottom, 1912,
Journ. Q. 21. C, p. 400, pi. 17, fig. 8.

PI. 16, fig. 6. A few fine examples placed amongst others which
are too opaque for me to be certain whether they belong to this
variation. Locality : Uncertain.

182 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC^

Lagena laevigata Reuss sp. var.

Lagena laevigata Reuss sp. var. Sidebottom, 1912, Journ. Q. M. 0. T
p. 400, pi. 17, fig. 7.

+ P1. 17, fig. 7. Very rare. Locality : Nos. 15, 34.

Lagena acuta Reuss sp. (PI. 16, fig. 7).

Fissurina acuta Reuss, 1862, p. 340, pi. 7, fig. 90, and F. apiculata r
p. 339, pi. 6, fig. 85.

Lagena acuta (including such as have only the slightest indica-
tion of the apiculate process) is found at almost all the localities..
The size and inflation of the tests, as well as their outlines, vary
greatly. Two at No. 14.

Lagena acuta Reuss sp. var. (PI. 16, fig. 8).

The chief feature of this variety is the curious oval marking at-
the base, on both sides of the test. It is very rarely so clearly-
shown as in the drawing. The tests are opaque or nearly so, and
when the shell-substance becomes very dense the markings
disappear, but if damped some trace of them can be detected.
Locality : Nos. 3-7, 9-11, 13 15, 29, 33, 34, 39, 40, 42, 44.

+ P1. 17, fig. 9. The mixing of this form w T ith that of fig. 10'
prevents me from giving the exact localities, but it is evidently
rather rare. They correspond with the Fissurina apiculata Reuss,.
1862, p. 339, pi. 6, fig. 85.

Lagena acuta Reuss sp. var. virgulata Sidebottom.

Lagena acuta Reuss sp. var. virgulata Sidebottom, 1912, Journ..
Q.M. C, p. 401, pi. 17, fig. 10.

+ P1. 17, tig. 10. This appears to occur at nearly all the
stations up to No. 22, after which it is extremely rare.

Lagena acuta Reuss sp. var.

Lagena acuta Reuss sp. var. Sidebottom, 1912, Journ. Q. M. C^
p. 401, pi. 17, fig. 11.

Locality : Nos. 3, 4, 6, 10, 11, 14, 24, 25, 34, 39.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 183

Lagena lucida Williamson sp. (PI. 16, rig. 9).

K iitosolenia marginata var. lucida Williamson, 1848, p. 17, pi. 2,
fig. 17.

There are nine examples which are nearly circular in outline.,
and subcarinate. Locality : No. 44.

PL 16, fig. 9. I believe this to be an elongate form of L. lucida,
in which the characteristic markings are only feebly represented.
The shell is very little compressed. Two or three specimens only
oocur. Locality : Uncertain.

One or two tests are present which are intermediate between
the type and the elongate form referred to above. Several are
apiculate. Locality : Nos. 1, 6, 14, 21, 22, 24, 38, 42, 43.

Lagena multicosta Karrer sp.

Fissurina multicosta Karrer, 1877, p. 379, pi. 16 6, fig. 20.
Fissurina bouei Karrer, p. 378, pi. 16 6, fig. 19.

The examples are small, and some are without the irregularity
of the costae characteristic of the type. Locality : Nos. 24, 29, 34,
35, 39, 42-44, and one or two of the earlier stations.

Lagena fasciata Egger sp. (PI. 16, figs. 10-13).
Oolina fasciata Egger, 1857, p. 270, pi. 5, figs. 12-15.

PI. 16, fig. 10. Beautiful specimens occur which have the mouth
protruding, and the orifice composed of a line of pores. The
bands are flush or nearly so. Large and small tests are on the
slide. Locality: Nos. 1, 3-5, 7, 10, 22, 44, and several other
stations which are uncertain.

PI. 16, fig. 11. An apiculate form w r hich is extremely rare.
The edge of the test is flattened, and has a very fine groove
running down its centre. The orifice appears to be composed of a
line of pores. Locality : Uncertain.

PI. 16, fig. 12. Slightly apiculate, the orifice large, and the
entosolenian tube divided at the end. The edges of the bands,
which are not interrupted at the base, appear to be somewhat
raised. When the test is opaque it is difficult to make out the
bands. Locality : Nos. 24, 34, 36, 43, 44 : frequent at No. 44.

PI. 16, fig. 13. The test is apiculate and the opaque bands
which appear to be flush with the surface are continuous that is,.

184 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

not interrupted at the base as is usual in the type-form. About
thirty specimens on the slide. Locality ; Nos. 42-44.

Lagena fasciata Egger sp. var. spinosa Sidebottom.

Lagena fasciata Egger sp. var. spinosa Sidebottom, 1912, Journ.
Q. M. C, p. 402, pi. 17, figs. 16, 17.

"*"P1. 17, fig. 16. One or two small specimens. Locality:
Uncertain.

+ P1. 17, fig 17. A fair number are present, but they are
mixed with L. staphyllearia, so I cannot give the localities. See
remarks * p. 402.

Lagena fasciata Egger sp. var. carinata Sidebottom (PI. 16,

figs. 14-16).

Lagena fasciata Egger sp. var. carinata Sidebottom, 1906, Mem.

Pro. Lit. Phil. Soc, Manchester, No. 5, p. 7, pi. 1, fig. 17.
Lagena fasciata Egger sp. var. carinata Sidebottom, 1912, Journ.

Q. M. 6\, p. 403, pi. 17, fig. 18.

Pi. 16, fig. 14. The test is compressed, and the keel becomes
more pronounced as it approaches the base of the shell. The
internal tube is attached to the back of the test. A few of the
examples are very fine, like the one chosen for illustration. The
curved bands seem to be nothing more than an innumerable
number of pores showing distinctly. In some of the smaller
examples these bands can hardly be distinguished. It is open to
question if these forms and the following (PI. 16, fig. 15) would not
be better placed under L. marginata. Locality : Nos. 1-3, 5-7,
10, 11, 13 22.

PI. 16, fig. 15. Test compressed, carinate. The entosolenian
tube is long and curled at its end. The bands are faintly marked
as in the preceding form. Locality : Nos. 2-5 ; common at No. 2.

PI. 16, fig. 16. A solitary example. The edges of the curved
bands are very slightly raised, and the shell becomes more com-
pressed as the orifice is approached. The keel is represented by a
fine ridge only. The specimen is not in a very good condition,
opaque patches interfering with the definition of the bands,
especially at their bases. Locality : No. 42.

+ PI. 17, fig. 18. Two or three examples found. The carina is
not pointed at the base as in the figure referred to. Locality :
Uncertain.

HENRY S1DEB0TT0M ON LAGENAE OF THE SOUTH-WEST PACIFIC. 185

Lagena staphyllearia Schwager sp.
Fissurirta staphyllearia Schwager, 1866, p. 209, pi. 5, fig. 24.

The non-carinate form is rare. The number of spines varies.
The tube is attached to one side, thus causing the orifice to be
eccentric. In a few instances of the carinate variety, where only-
two spines are present, it is impossible to separate them from the
Fissurina bicaudata Seguenza, which is generally placed with L.
man/biota. Locality Nos. 1-7, 9-12, 15-25, 29, 33, 34, 36, 37,
39-43.

The variety with either the ketl or the lower part of the test
serrated or partially fimbriated is not so frequent, but occurs at
many localities. The orifice is central and the sides of the test
are only slightly carinate. Locality : Nos. 5-8, 10, 11, 14, 15, 18,
19, 21, 22, 24, 33, 34, 40, 43.

+ P1. 17. fig. 19. Very rave. Locality : Nos. 2, 3, 15, 22.

+ P1. 17, fig. 21. This peculiar variety is rather rare. The
tests are semi-opaque. There is a short entosolenian tube.
Locality : Nos. 5-11, 13, 21, 23, 25, 36, 39, 40.

+ P1. 17, figs 22, 23. See remarks * p. 403. Locality: Nos.
4-6, 8, 10, 22, 23, 33, 39.

Lagena staphyllearia Schwager sp. var. quadricarinata

Sidebottom.

Lagena staphyllearia Schwager sp. var. quadricarinata Sidebottom,
1912, Journ. Q. M. C, p. 404, pi. 21, fig. 16.

Locality .- Nos. 2, 5-7, 9, 10, 12, 13, 21, 38, 41.

Lagena unguiculata Brady.

Lagena unguiculata Brady, 1881. Quart. Journ. Micr. Sci., vol. 21,

(N.S.), p. 61.
-Lagena unguiculata Brady, 1884, p. 474, pi. 59, fig. 12.

See remarks + p. 404. Locality : Nos. 5-10.

Lagena quadrata Williamson sp.
-Entosolenia marginata var. quadrata Williamson, 1858, p. 11, pi. 1,
fig. 27.
Both the carinate and non-carinate form are present. Locality :
Nos. 15, 22, 24, 25, 34, 37, 40, 42-44.

Journ. Q. M. C, Series II. No. 73. 13

186 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

There are several' examples which have a short neck and the
orifice carrying a short spine at either side. Three or four
specimens are similar to the one figured by Mr. Millett in his
Malay Report, 1901, p. 496, pi. 8, fig. 18.

Lagena marginata Walker and Boys sp. (PI. 16, figs. 17-20,

fig. 18, trifacial form).

" Serpula {Lagena) marginata" Walker and Boys, 1784, p. 2,.
pi. 1, fig. 7.

This species is exceedingly well represented in these gatherings,
and in one form or another is found at nearly all the stations.
The shape of the body of the test varies from flattened to globular,
and in outline from circular to elongate-pyriform, the carination
from a fine ridge to a very broad wing. The situation and form
of the orifice are variable. Apiculate examples are present and
some have the keel acuminate at the base.

PI. 16, fig. 17. This agrees fairly well in outline with Fissurina
paradoxa Seguenza, 1862, pi. 2, fig. 7. The Fissurina bicaudata
Seguenza, 1862, pi. 2, fig. 16, is also represented, and it is difficult
in some cases to separate this from L. staphyllearia.

PI. 16, fig. 18. A trifacial form. If anything, the three faces
of the body are somewhat concave ; one would rather expect them
to be convex, judging from trifacial examples that occur in other
species. The specimens vary very little. Locality ; Nos. 2-4,
8-10, 14, 15, 22, 29, 34, 36, 39, 40.

PI. 16, fig. 19. The edge of the test is flattened, the orifice
fissurine. In some positions it has the appearance of being
slightly bicarinate, but I do not think it is so. Locality : Nos.
42, 43.

PI. 16, fig. 20. This minute variety has a comparatively large
orifice, which is much compressed and opens out on one side of
the median line ; the tube is attached to the back of the test,
which is very slightly carinate. The test is moderately com-
pressed and curiously tucked in at its base. The specimens are
mixed with others very similar to them, but which have the
orifice central and the tube short and straight. There are other
forms on the same square, so I cannot give the exact localities.
The two forms mentioned are rare. Both were found at a station
later in the series than ISTo. 22.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 187

Lagena compresso-marginata Fornasini (PI. 16, fig. 21).

Lagena compresso-marginata Fornasini, 1889, Minute Forme di
Riz. Retic. nella Mama Plioc. del Ponticello di Savena,
Bologna, fig. 16.

PI. 16, fig. 21. This is rather a stoutly-built form. The aperture
is fissurine and the test apiculate. Locality : Nos. 22, 24.
Rather rare.

There are a few very small examples that appear to be almost
identical with Fornasini's figure. Locality : Uncertain.

+ PI. 17, fig. 30. Only two or three found. Locality: Nos.
42, 44, and two or three examples at one or two other stations.

+ PI. 17, fig. 31. Very rave. Locality ; Nos. 2, 4.

*** PI. 18, fig. 1. Very rare. See remarks + p. 406. Locality ;
Nos. 2, 5, 7, 19, 24.

Lagena marginata Walker and Boys var.

Lagena marginata Walker and Boys var. Sidebottom, 1912,
Journ. Q. M. C, p. 407, pi. 18, figs. 4, 5.
Locality: Nos. 4-6, 10-13, 16, 17, 19-23, 25, 36, 40.

Lagena marginata Walker and Boys var. catenulosa Chapman

(PL 16, fig. 22).

Lagena marginata var. catenulosa Chapman, 1895, p. 28, pi. 1, fig. 5.

Lagena marginata Walker and Boys var. catenulosa (Chapman)

Sidebottom, 1912, Journ. Q. M. C, p. 407, pi. 18, fig. 6.

PI. 16, fig. 22. Four examples occur. The one chosen for
illustration hardly shows a trace of the chain-pattern, and the
test is free from exogenous shell-growth. The others show the
chain-pattern. One of the specimens has the body of the test
covered with exogenous beads. The few tubuli shown in the
drawing are caused, I believe, by the borings of some animal.
Locality : Nos. 1, 5, 10.

Lagena marginata Walker and Boys var. raricostata

Sidebottom.

Lagena marginata Walker and Boys var. raricostata Sidebottom,
1912, Journ. Q. M. C, p. 408, pi. 18, figs. 8, 9.

*' r PI. 18, fig. 8. Over twenty specimens are on the slide.
Locality : Nos. 1-3.

18S HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Lagena marginata Walker and Boys var. striolata Sidebottom.

Lagena marginata Walker and Boys var. striolata Sidebottom,
1912, Journ. Q. M. C, p. 408, pi. 18, figs. 10, 11.

+ P1. 18, fig. 10. Locality: Nos. 1, 3, 4, 15, 18-20, 22-25, 34,
35, 38, 42-44 ; frequent at Nos. 42, 43.

+ PI. 18, fig. 11. Locality : Nos. 23, 24, 42.

Lagena marginata Walker and Boys var. elegans Sidebottom.

Lagena marginata Walker and Boys var. elegans Sidebottom,
1912, Journ. Q. M. C, p. 409, pi. 18, fig. 12.

Locality : Nos. 14, 19, 20 ; frequent at No. 14.

Lagena marginata Walker and Boys var. retrocostata

Sidebottom.

Lagena marginata Walker and Boys var. retrocostata Sidebottom,
1912, Journ. Q. M. C, p. 409, pi. 18, fig. 13.

Locality : One specimen at No. 2, and one other, station un-
certain.

Lagena marginata Walker and Boys var. semimarginata

Reuss.

Lagena No. 64, von. Schlicht, 1870, p. 11, pi. 4, figs. 4-6; and

Xo. 65, p. 11, pi. 4, figs. 10-12.
Lagena marginata var. semimarginata Reuss, 1870, p. 468.

An altogether unsatisfactory variation. It occurs in several
forms at a few stations ; that figured in the Challenger Report,
pi. 59, fig. 19, occurs at No. 44.

Lagena marginata Walker and Boys var. seminiformis

Sch wager.

Miliola stiligera Ehrenberg (?) 1854, pi. 31, fig. 6.
Lagena seminiformis Schwager, 1866, p. 208, pi. 5, fig. 21.

Four large examples occur, similar to those figured in the
Challenger Report, pi. 59, figs. 28-30. Locality; Nos. 5, 16, 17.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 189

"*" PI. 18, fig. 16. Extremely rare, only one or two being found.
Locality ; Uncertain.

"i" PI. 18, fig. 17. Locality-. Nos. 1-3, 15. Three examples at
two or perhaps three of the four stations indicated ; also six at a
few other uncertain localities.

+ PI. 18, fig. 18. Locality: Nos. 1, 3, 13, and several others.
Very rare.

** PI. 18, fig. 19. Several have the central spine at the base of
the same length as the other two. Locality : Nos. 2, 3, 6-8, 10,
11, 24, 34-36.

Lagena marginato-psrforata Seguenza (PI. 16, figs. 23-25).
Lagena marglaato-perforata Seguenza, 1880, p. 332, pi. 17, fig. 34.

Very numerous. The variety with no keel is rare. The shape
of the test varies a good deal as regards compression and length.
In a few cases, fine lines, running the length of the test, make
their appearance. At the edge of the test, the markings are
sometimes arranged in a line. Locality : Nos. 1, 2, 4, 5, 7-15, 19,
20, 22-25, 29, 38-40, 42-44.

PI. 16, fig. 23. This is nearly circular in section near the base,
and becomes compressed as the orifice is approached. Tube
straight. Ptare. Locality : No. 14.

PI. 16, fig. 24. In this example fine pores are seen, but with
few exceptions the centre of each face of the test is free from
them. One specimen is in the trifacial condition. Locality ;
Nos. 23-25, 29, 33, 36, 38, 39.

PI. 16, fig. 25. Test well compressed, subcarinate. Except for
the two lines of pores that run round the test close to its edge,
the faces are almost free from them. The shell is partially
clouded. Fairly frequent. Locality : Uncertain.

Lagena Wrightiana, Brady.

Lagena Wrightiana Brady, Quart. Journ. Micr. ScL, vol. 21,1881,

p. 62.
Lagena Wrightiana Brady, 1884, p. 482, pi. 61, figs. 6, 7.

The central part of the faces of the test is not always smooth.
Very rare. Locality : Nos. 37, 42, 43.

190 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Lagena lagenoides Williamson sp. (PI. 16, figs. 26-29, and

pi. 17, fig. 1).

Entosolenia marginata Walker and Boys var. lagenoides
Williamson, 1858, p. 11, pi. 1, figs. 25, 26.

This and its numerous variations are well represented. PI. 16,
figs. 26, 27. I was tempted to place these under L. marginata,
but the appearance of the wing caused me to hesitate and to
submit a specimen to Mr. Earland for examination. He reported
that the wing was tubulated, being " infiltrated with amorphous
carbonate of lime subsequent to the death of the animal." Mr.
Millett considers that if tubuli are present " their affinity would
be with L. lagenoides rather than with L. marginata." Besides
the two forms figured, both large and small circular examples
occur in the same condition, only with the tubuli showing more
plainly.

PI. 16, fig. 28 represents one of the small examples. There are
also specimens which are apparently of exactly the same form, in
which the tubuli, if present, must be extremely minute. It would
appear therefore necessary to submit all such forms to critical
examination. Locality : Nos. 5-7, 11, 14, 15, 18-22.

PI. 16, fig. 29. In this instance the keel is twisted at the base.
Four specimens found. Locality : Uncertain, but after station
No. 22.

PI. 17, fig. 1. The test is well compressed and the orifice also.
Entosolenian tube short and curled. Locality : Ncs. 42-44 ;
frequent at Nos. 43, 44.

+ P1. 18, fig. 22. The form occurring is very similar to the
figure referred to. It is rather smaller and the keel is narrower
and thicker ; the neck and phialine orifice are the same. Locality ;
Nos. 1-3, 42-44.

Six large specimens similar to the Challenger Report figure,
pi. 60, fig. 14, are also present. Very rare. Locality : Nos. 2,
22, 24.

Another set is similar to +pl. 19, fig. 4, but the tests are not
striated. Frequent. Locality : Nos. 2-8, 11.

+ PI. 18, fig. 23. See remarks, +p. 412. Locality : Nos. 2, 36,
38, 39.

+ P1. 18, fig. 29. Typical examples are very rare and not so

HENRY SIDEBOTTOM OX LAGENAE OF THE SOUTH-WEST PACIFIC. 191

large as the specimen referred to. Locality : No. 3, and either
No. 35 or 39.

Besides the above, there are a few specimens which are much
smaller, especially in the width of the test. Locality : Nos. 17,
19, and one or two other stations.

Lagena lagenoid.es Williamson sp. var. nov. duplicata

(PI. 17, fig. 2).

The test is bicarinate ; aperture oval and the keels tubulated.
Six specimens found. Locality : Nos. 24, 37.

Lagena lagenoides Williamson sp. var. tenuistriata Brady.

Lagena tubulifera var. tenuistriata Brady, 1881, Quart. Joiirn.

Micr. Sci. vol, 21 (N.S.), p. 61.
Lagena lagenoides Williamson var. tenuistrata Brady, 1884, p. 479,

pi. 60, figs. 11, 15, 16.

*P1. 19, fig. 4. Very frequent. These correspond to the
Challenger Report, pi. 60, fig. 11. The trifacial form also occurs.
Locality ; Nos. 1-11, 13, 14, 17, 21-24, 29, 31, 33-35, 37, 39-41.

There is another set of specimens which are not quite so large
and have the costae on the body of the test, farther apart.
Locality : Nos. 14, 15, 17, 18.

There are a few large specimens very similar to the Challenger
Report, pi. 60, fig. 15. In the stouter examples the fine costae
coalesce to such an extent that the surface has a pitted appear-
ance. Locality: Nos. 2, 8, 11, and one or two other stations.

Lagena formosa Schwager (PI. 17, figs. 3-7).

Lagena formosa (pars) Schwager, 1866, p. 206, pi. 4, fig. 19.
Lagena formosa (Schwager) Brady, 1884, p. 480, pi. 60, figs. 10,
18-20.

This is present in many forms ; some show the raised border
punctate, others do not. See remarks **" p. 414.

PI. 17, fig. 3. In this, which is obviously of the same kind as
fig. 18, pl. 60, in the Challenger Report, the raised border is
absent. Others agree with this figure, also with the Challenger
Report, fig. 20.

Several very fine specimens are intermediate between fig. 18
and L. formosa var. favosa Brady, on the same plate, fig. 21.

192 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACTFIC

They are heavily punctate at the base of the neck, and costae just
start to run clown the keels. Many small examples occur, which
come under this unsatisfactory species, but as they are mixed on
the various squares I can only give the stations for the whole
series. Locality : Nos. 1-8, 10, 11, 13, 14, 17, 21, 23-25, 29,
37, 39-41, 43.

PI. 17, fig. 4. The keel splits near the top, and the space thus
formed is filled with shell-growth. The specimens are not in a
satisfactory condition for examination, so I cannot say if the
tubuli in the keel occupy the whole of the space. The punctate
border does not seem to be raised, and it shows clearer in substance
than the rest of the test. I believe this is the same as Challenger
Report, pi. 60, fig. 10. Locality : No. 44.

PI. 17, fig. 5. T am inclined to believe that the keel has broken
away in these specimens, of which there are seven. They are all
in the same condition ; the drawing shows how the keel has
begun to split. Locality . Nos. 43, 44.

+ PI. 18, fig. 24. I am now inclined to believe that in this
case also the keel has become fractured.

PI. 17, fig. 6. This has a likeness to the preceding pi. 17, fig. 5.
The keel, which commences at the neck, soon splits and joins the
two borders ; the space between them is filled with shell-growth.
The test has a very compact look and the tubuli show clearly.
Rare. Locality : Nos. 42, 43.

PI. 17, fig. 7. A solitary specimen in good condition. The keel,
commencing at the orifice, dies away about half-way down the
test. A few well-marked pores are scattered on each face of the
test. At the base are several short costae. Locality ; No. 37.

+ P1. 19, fig. 9. See remarks, + p. 414. Frequent. Locality :
Nos. 1, 2, 10, 11, 14, 17-19, 22. Over twenty examples occur after
station No. 22, but the exact stations are uncertain.

Lagena formosa Sch wager, var. (PI. 17, fig. 8).

The drawing of this variety must be taken more or less as
diagrammatic. The test, which has three keels (the central one
commencing at the aperture) is in an opaque condition. The
spaces between the keels are filled with shell-growth. The tubuli
hardly show, unless the shell be moistened. The body of the test
has fine costae running lengthwise, and is finely pitted. There*

HENRY SIDEBOTTOM ON LAGEXAE OF THE SOUTH-WEST PACIFIC. 193

are only two specimens and they are exactly alike. Locality .-
No. 40.

Lagena formosa Schwager var. comata Brady.
Lagena formosa var. comata Brady, 1884, p. 480, pi. 60, tig. 22.

A few large specimens occur very similar to the Challenger
examples, pi. 60, tig. 22. Locality : Nos. 5, 6, 33, 34.

+ P1. 19, fig. 11. A single example. Locality: Uncertain.

+ P1. 19, fig. 12. Very rare. Locality : Nos. 6, 10, 22, and
one or two stations which are uncertain.

Lagena squamoso-alata Brady (PI. 18, fig. 20).

Lagena squamoso-alata Brady, 1881, Quart. Journ. Jlicr. Sci.

vol. 21 (N.S.), p. 61.
Lagena squamoso-alata Brady, 1884, p. 481, pi. 60, fig. 23.

A single example occurs, which is typical, except that the
produced neck is absent, having most probably been broken off.
Locality : No. 23.

PI. 18, fig. 20. Besides the above typical specimen, there are
twenty-two tests which are smaller and not so robust. They
answer to Brady's description of the species. The pittings on the
body of the test have a tendency at times to arrange themselves
in lines. The raised border appears to be punctate. It is
difficult to make out the markings on the wings, owing to debris,
but they can be detected in some of the specimens. I believe the
wings to be cellulated. Brady, in the Challenger Report, only
mentions that they have radiate markings ; but on examining the
edges of my typical specimen it is apparent that the wings are
cellulated. I take this form to be simply a variety of L. formosa.
One example is in the trifacial condition. Locality ; Nos. 24, 25,
34, 36.

Lagena quadrangularis Brady.

Lagena quadrangularis Brady, 1884, p. 483, pi. 114, fig. 11.
Lagena quadrangularis (Brady) Millett, 1901, p. 625, pi. 14,
% IT.

A single typical specimen, but the neck appears to be fractured.
Locality ; Either No. 14 or No. 22.

194 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Lagena Orbignyana Seguenza sp. (PI. 17, figs. 9-11).

Entosolenia mdrginata (pars) Williamson, 1858, p. 10, pi. 1, figs.

19, 20.
Fissurina Orbignyana Seguenza, 1862, p. 66, pi. 2, figs. 25, 26.

This occurs in many forms. Some of the specimens are similar
to the Challenger Report, pi. 59, figs. 25, 26. Numerous small
varieties also are present. In some the side keels are little more
than slightly raised ridges.

PI. 17, fig. 9. This is a very neat and compact variety.

The test is moderately compressed. Locality : Nos. 42-44 ;
frequent at Nos. 42, 44.

PI. 17, fig. 10. I take this to.be a variety of L. Orbignyana, in
which the central keel has split soon after leaving the orifice.
The body of the test is much compressed, and is roughened. The
entosolenian tube is long and attached. The split keel is entirely
blocked w T ith debris, or shell-growth. Two examples found.
Locality : No. 38.

PI. 17, fig. 11. A neat form. The central keel is emarginate
at the base, at the middle of which one or two small spines
project. The two subsidiary keels are not generally continuous.
There are over one hundred specimens. Locality : Nos. 1, 2, 4-13,
21, 23, 26, 29, 33, 34, 38, 39.

Lagena Orbignyana Seguenza sp. var. lacunata Burrows and

Holland (PI. 17, fig. 12).

Lagena lacunata (Burrows and Holland) Jones, 1895, p. 205, pi. 7,
fitf 12

One set agrees exactly with fig. 1, pi. 60 of the Challenger
Report, which Messrs. Burrows and Holland point out in the
above reference, is misnamed as L. castrensis Sch wager. Locality :
Nos. 42-44 ; frequent at No. 44.

A few small examples are occasionally met with in which the
pittings are numerous and minute, and the keels very feebly
developed. Locality : Uncertain.

PI. 17, fig. 12. I am treating this as a form of X. Orbignyana
var. lacunata, but it appears to have one of the characteristics of
L. annectens (Burrows and Holland) Jones, 1895, for the band
round the body of the test appears to be very slightly concave.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 195

The edges of the band are just raised above the surface, and the
space between is roughened. It will be noticed, by reference to
the Challenger figure, pi. 60, fig. 1, that there is a ridge, or minor
keel, between the side keel and the central one, and I take my
specimens to be in the same condition, only the inner ridge is
quite close to the central keel. The body of the test is finely
pitted all over. The aperture is large, compressed and lipped.
In two cases the keel is serrated all round, but it is doubtful if
this is natural. The tube is attached. Frequent. Locality :
Nos. 42, 43.

Lagena Orbignyana Seguenza sp. var. Walleriana Wright.

Lagena Orbignyana sp. var. Walleriana Wright, 1886, Proc. JR. Irish
Acad., ser. 2, vol. iv., p. 611, and 1891, p. 481, p. 20, fig. 8.

In all the specimens the typical boss is replaced by a ring,
which is very slightly raised. Locality: Nos. 2, 22, and one or
more of the three stations, Nos. 42-44.

Lagena Orbignyana Seguenza sp. var. unicostata Sidebottom.

Lagena Orbignyana Seguenza sp. var. unicostata Sidebottom,
1912, Journ. Q. M. C, p. 417, pi. 19, fig. 22.

The single costa in this case runs the whole length of the body
of the test. Very rare. Locality ; Nos. 18, 22.

Lagena Orbignyana Seguenza sp. var. pulchella Brady

(PI. 17, fig. 13).

Lagena pulchella Brady, 1866, Rept. Brit. Assoc. (Nottingham),

p. 70.
Lagena pulchella Brady, Annals and Mag. Nat. Hist., 1870, p. 294,

pi. 12, fig. 1.

The largest specimens are very similar to L. Orbignyana var.
variabilis Wright, 1891, pi. 20, fig. 9, but the costae are irregular
and cover the whole of the body of the test ; sometimes there is
a fine ridge showing between the main keel and the side keels.
Very rare. Locality : Uncertain.

A smaller set is frequent, with few and irregular costae. The
side keels amount to little more than slight ridges. Locality :
No. 44.

196 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC*

A few very small examples are also present.

PI. 17, fig. 13. This solitary example has the eostae well raised,
and as they are irregular I have placed it under the above head-
ing. The side keels are only just apparent. Locality : No. 44.

+ P1. 19, fig. 24. Very rare. See remarks + p. 418. Locality .-
Nos. 1, 38.

Lagena Orbignyana Seguenza sp. var. clathrata Brady

(PI. 17, fig. 14).

Lagena clathrata Brady, 1884, p. 485, pi. 60, fig. 4.

The type-form occurs, but is always rare, except at No. 43,
where eleven were found. Locality: Nos. 17, 18, 24, 29, 35, 37,
38, 43, 44.

A few very small specimens are present, but they are not
typical. Others are minute, with numerous fine eostae either
straight or curved, these latter resembling L. variabilis, as Mr.
Millett remarks in his Malay Report, 1901, p. 628.

PL 17, fig. 14. I think this may be brought under the above
heading. The test is compressed and has three keels ; these
stand out more than the three eostae which run down each face
of the test. Locality : Nos. 8, 10-14 ; frequent at No. 8.

Lagena Orbignyana Seguenza sp. var. variabilis Wright.

Lagena Orbignyana sp. var. variabilis Wright, 1890, p. 482, pi.
20, fig. 9.

Except that the side keels are not so well developed, and the
striae are very numerous, the specimens are fairly typical. In
several instances the striae are inclined to cover the body of
the test, and in others they are either absent or scarcely per-
ceptible. Locality .- 2, 5-7, 10-14, 16-18, 24, 29, 34, 35.

Lagena Orbignyana Seguenza sp. var. (PI. 17, fig. 15).

The test is only slightly compressed ; the main keel, which
starts at the orifice, splits as it approaches the body of the test.
Very fine bars cross the space thus formed. Between the cross-
bars is a well-marked circular depression. Besides the side keels
there are two semicircular eostae, one of these on each face of
the test. At the base is an irregular circular projection to which
the keels are attached. The wall of this projection is thin.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 197

Onlv two specimens were found, each of them badly fractured.
Both have been utilised in preparing the illustration, which must
be considered as a drawing of a restored specimen. Locality;
Uncertain.

Lagena bicarinata Terquem pp. (PI. 17, figs. 16, 17).
Fissurina bicarinata Terquem, 1882 7 p. 31, pl. 1 (9), fig. 24.

The type-form does not appear to be present.

PI. 17, fig. 16. The tests are in a very opaque condition.
Locality: Nos. 23, 24, 33, 34, 40.

PI. 17, fig. 17. There are two or more spines at the base.
Eleven specimens are in good condition. Locality : Nos. 2-3.

+ PI. 19, fig. 27. See remarks + p. 419. Locality ; Nos. 2-4.

A few also occur, very similar to these, except that the body of
the test is more circular in outline. Locality : Uncertain.

Lagena bicarinata Terquem sp. var. (PI. 17, fig. 18).

Test bicarinate. The faces of the test are slightly convex, and
the two keels slope towards their edges, the effect being that the
test appears to have a boss on either face. Orifice much com-
pressed and composed of a row of pores. A solitary specimen.
Locality : No. 37.

Lagena bicarinata Terquem sp. var. (PI. 17, fig. 19).

Test bicarinate and apiculate, with a row of very short tubular
projections running round the edge of the test between the keels.
The test becomes more compressed as the orifice is approached.
Two examples only occur. The neck appears to be broken olT in
both cases. Locality: No. 43.

Lagena bicarinata Terquem sp. var. (PI. 17, fig. 20).

Test bicarinate, the keels generally dying away as they
approach the orifice, which is composed of a series of fine pores.
I cannot say if the fine bands, which adorn each face of the test,
a,re raised or not. Bands of different nature and length are
found on other species besides L. fasciata, so I prefer to place this
form under L. bicarinata, instead of treating it as L. fasciata in
the bicarinate condition. Locality : Nos. 1-10, 13, 15, 16.

198 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC

Lagena auriculata Brady (PI. 17, figs. 21, 22, and pi. 18,

fig. 1).

Lagena auriculata Brady, 1881, Quart. Journ. Jlicr. Sri., vol. 21

(N.S.), p. 61.
Lagena auriculata Brady, 1884, p. 487, pi. 60, figs. 29, 31, 33.

This is largely represented, especially in its variations ; inter-
mediate forms occur which it would be interesting to figure.

PI. 17, fig. 21. In this solitary specimen the wing has divided
at a point a little above the body of the shell. Locality ; No. 2&
or No. 39.

PI. 17, fig. 22. A neat form which appears to be strongly
built. The shell is moderately compressed. The entosolenian
tube, when present, is very short and straight. The orifice is
crowned with a boss, and the loops at the base are feebly
represented. Nine specimens occur. Locality ; Nos. 2, 10.

PI. 18, fig. 1. A stoutly-built form. The test is subcarinate,.
and the orifice situated in a depression. The two loops at the
base are feebly developed. Very rare. Locality ; Uncertain, but-
after station No. 23.

"** PI. 20, fig. 4. A few examples resemble this variation, the
keel being continuous round the edge of the test. Locality : Nos.
23, 24, 26, 36, 38, 40, 42, 43.

"*" PI. 20, fig. 5. There are twelve examples, closely resembling
this figure, but having no small wings at the top of the test.
Locality : Nos. 24, 29, 34, 36, 39-41.

**" PI. 20, figs. 7. 8. A large number are similar to these forms
and to Challenger Report, pi. 60, fig. 29. Locality : Nos. 2-4,.
6-12, 17-24, 26 29, 33 35, 38 43.

+ P1. 20, figs. 9, 10. Some forms present lie more or less
between the two figures given at this reference. Locality; Nos.
2-6, 6-11, 17, 18, 21, 22.

+ P1. 20, figs. 11, 12. Only two or three specimens are near
+ fig. 11 ; all the rest, and there are over eighty, are like + fig. 12.
Locality .- Nos. 1-11, 22, 23, 33, 34, 37, 39. Most of them were
found at Nos. 1-11.

"*"P1. 20, fig. 13. Nine examples occur, and one is in the
trifacial condition. Locality ; Nos. 1, 38, 42 44 : the trifacial
specimen at No. 43.

*P1. 20, fig. 14. Eight specimens found. Locality; Nos. 1-4.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 199

Lagena auriculata Brady var. nov. caudata (PI. 18, figs. 2, 3).

Test compressed, the lower part of the body faintly striated.
A single long spine, probably always bent more or less to one
side, projects at the base. Orifice situated at the end of a long
neck. In fig. 2 the basal spine is partly broken off.

The faint striation seems to indicate an affinity with L. auricu-
lata var. costata Brady, but in order to avoid giving subvarietal
names, I have treated it as a variation of L. auriculata.
Locality : No. 2.

Lagena auriculata Brady var. nov. circunicincta (PI. 18, fig. 4).

Test compressed, subcarinate, except at the lower edge and
base, where the keel is well developed. A few costae run across
each face of the test. Orifice oval. Entosolenian tube long and
curved. Four specimens occur. There are six tests on the
square, but two do not belong to the same variety. Locality .-
No. 43, and one of the following stations : Nos. 38, 42, 44, but
which one is doubtful.

Lagena auriculata Brady var. nov. clypeata (PI. 18, fig. 5).

Test compressed, carinate. Orifice oval. Two raised oval
rings (sometimes slightly irregular) on each face of the shell.
The loops at the base small. Entosolenian tube long and curved.
It is easy to miss noticing the loops. The tests vary a little
from one another in outline. The keel is not quite so wide as
indicated in the drawing.

About twenty specimens are arranged on the same square as a
number of L. Orbignyana sp. var. Waller iana Wright, for which
they may have been temporarily mistaken. Locality : The
majority must have been found either at Nos. 42 or 43, or both.

Lagena auriculata Brady var. Sidebottom (PI. 18, fig. 6).

Lagena auriculata Brady var. Sidebottom, 1912, Journ. Q. M. C. r
p. 421, pi. 20, figs. 15-18.

Pi. 18, fig. 6 and * pi. 20, fig. 15. I have figured one of
average size. There are often a few spines at the base.
Locality ; Nos. 4, 23, 24, 38-44.

A few elongate examples occur. Locality ; Nos. 2. 3-

.200 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC

Several approach + pi. 20, fig. 18. Locality : Uncertain.

+ PI. 20, fiff. 17. A number are near this form, and mixed
^vvith them are several identical with Mr. Millett's Malay Report,
pi. 14, fig. 15. Locality : Nos. 1-4.

A few elongate specimens occur, the body being striated, or
^wrinkled, as indicated in the figure. Locality : Nos. 8, 9, 11.

Lagena auriculata Brady var. arcuata Sidebottom.

Lagena auriculata Brady var. arcuata Sidebottom, 1912, Journ.
Q. M. C, p. 421, pi. 20, figs. 19, 20.

+ PI. 20, fig. 19. The specimens differ from the figure, as the
arches radiate from the base. Locality : Nos. 4-7, 9, 10.

Lagena auriculata Brady var. costata Brady.

Lagena auriculata Brady var. costata (Brady) Sidebottom, 1912,
Journ. Q. M. C, p. 422, pi. 20, figs. 21, 22.

* Pi. 20, fig. 22. See remarks, + p. 422. Locality : Nos. 23,
24, 29, 33, 39~ 42.

Lagena auriculata Brady var. duplicata Sidebottom

(PI. 18, figs. 7, 8).

Lagena auriculata Brady var. duplicata Sidebottom, 1912, Journ.
Q. M. a, p. 422, pi. 20, fig. 23.

Pi. 18, fig. 7. The loops in this case extend from the base
almost to the neck. At the first glance, I took the specimens to
be L. Orbignyana, as in some of the specimens debris or shell-
growth partially covered the loops, the inner sides of which are
quite close to the keel ; a closer examination of other examples,
which are free from debris, show the loops to be complete.
The tests, of which there are tan, are large. Locality : No. 42.

Note. The above might, with equal propriety, be treated as
a carinate form of L. alveolata var. separans Sidebottom, 1912,
+pl. 21, fig. 4.

PL 18, fig. 8. This differs from + PI. 20, fig. 23, chiefly in the

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 201

absence of the carina. Very rare. Locality : Nos. 29. 34, 39.
Two or three were found at other stations besides those indicated.

Note. Several examples occur almost identical with the above ;
the only difference being that the loops merge together as in
L. alveolata, and so must be treated as such.

* PI. 20, fig. 23. One specimen. Locality: Uncertain.

Lagena fimbriata Brady (PL 18, tig. 9).

Lag ena fimbr lata Brady, Quart. Journ. Micr. Sci., vol. 21 (N.S.),

1881, p. 61.
Lagena fimbriata Brady. 1884, p. 486, pi. 60, figs. 26-28.

Two specimens occur similar to the Challenger Report, pi. 60,
fig. 28. Locality : Uncertain.

Pi. 18, fig. 9. This is a neat, small, compactly built variety,
and the fimbriated portion does not appear liable to get fractured.
The tube is curled upon itself. The test is moderately com-
pressed, and the opening at the base is very narrow. This variety
must not be confused w T ith pi. 20, fig. 28. Locality : Nos. 31, 43,
44 ; frequent at No. 44.

+ PI. 20, fig. 24. Two examples only occur. Locality :
No. 31.

+ P1. 20, fig. 25. Eight specimens. Locality : One or more of
the following stations : Nos. 5, 6, 22.

+ PI. 20, fig. 26. Four very fine examples occur. Locality :
Nos. 4, 6, 8, 10.

Three specimens, with the base more pointed and the opening
more contracted, are also on the slide. Locality : Nos. 7, 10, 12.

Lagena fimbriata Brady var. nov. duplicata (PI. 18, fig. 10).

Test compressed, ovate. There are two narrow loops, side by
side, across the width of the test at its base. Tube curled on
itself. I think the walls of the loops are tubulated, but cannot
be quite certain about it. A solitary specimen. Locality:
Uncertain.

There is another test which has the orifice wider, and the tube
short and straight. The loops are in the same position, but so
feebly represented that it is doubtful whether it belongs to the
above variety.

Journ. Q. M. C, Series II. No. 73. 14

202 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Lagena fimbriata Brady var. occlusa Sidebottom.

Lagena fimbriata Brady var. occlusa Sidebottom, 1912, Journ..
Q. M. C, p. 423, PI. 20, figs. 27, 28.

+ PI. 20, fig. 27. Common. Most of the specimens have the
opening at the base more open than in the illustration. See
remarks, + p. 423. Locality: Nos. 1-4, 6-13, 15, 17, 19, 22, 24,
25, 29, 31, 33-35, 37-42.

Lagena alveolata Brady (PI. 18, figs. 11, 12).
Lagena alveolata Brady, 1884, p. 487, pi. 60, figs. 30, 32.

PL 18, fig. 11. The tests are large and strongly built. All are
in the apiculate condition. The dotted line indicates the
boundary of the chamber, thus showing the thickness of the
wall. Orifice oval. Twelve examples occur. Locality : Nos. 1, 5.

PL 18, fig. 12. There are a large number present. The tests
are fairly well compressed. The chief peculiarity is that, though
the entosolenian tube is straight, the orifice opens out well below
the median line. The part above the j orifice is sharpened. The
loops at the base are small, and their outer edges do not project
nearly so far as does the central carina. Locality : Nos. 1-15,
17-20.

"** PL 21, fig. 1. Unfortunately the specimens are mixed with
another species, so that the stations at which they were found
are uncertain. There are a fair number on the slide.

**" PL 21, fig. 2. Good examples are present. Locality : Nos. 1,
3-5, 7, 10, 16, 17.

Lagena alveolata Brady var. carinata Sidebottom.

Lagena alveolata Brady var. carinata Sidebottom, 1912, Journ.
Q. M. C, p. 424, pi. 21, fig. 3.

This form is very rare in this collection. Locality : Nos. 24,.
39, 40.

Lagena alveolata Brady var. substriata Brady.

Lagena alveolata var. substriata Brady, 1844, p. 488, pi. 6, fig. 34.

A single specimen. It is not quite typical, the neck of the
test being more produced than in the Challenger figure.
Locality : No. 39.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 203

Lagena alveolata Brady var. separans Sidebottom.

Lagena alveolata Brady var. separans Sidebottom, 1912, Journ.
Q. M. C, p. 425, pi. 21, fig. 5.

Locality: Nos. 1-3, 5, 6, 17-20, 23-25, 34, 38.

Lagena clypeato-marginata Rymer-Jones var.

Lagena clypeato-mavginata Rymer- Jones var. Sidebottom, 1912,
Journ. Q. 21. C, p. 425, pi. 21, fig. 6.

Several examples occur. Locality : Uncertain.

Lagena magnifica Sidebottom.

Lagena magnifica Sidebottom, 1912, Journ. Q. M. 6'., p. 425,
pi. 21, fig. 8.

A few of the specimens are in the transparent condition.
Locality : ]S"os. 1-5, 7.

Lagena Elcockiana Millett.

Lagena Elcockiana Millett, 1901, p. 621, pi. 14, figs. 5, 6.
Lagena Elcockiana (Millett) Sidebottom, 1912, Journ. Q. M. C,
p. 426, pi. 21, fig. 9.

A single specimen. Locality : Uncertain.

Lagena galeaformis Sidebottom.

Lagena galeaformis Sidebottom, 1912, Journ. Q. M. C, p. 426,
pi. 21, figs. 11, 12.

+ P1. 21, fig. 12. Only the trifacial form appears to be repre-
sented in these gatherings. Locality : Nos. 1-3.

There are a few tests which may, or may not, be the bifacial
form of this species. I have included them under **"pl. 20, fig. 17,
on page 421. They are not so stout as this figure represents,
and the side keels are entire as far as the tubular process.

Lagena protea Chaster.

Lagena protect Chaster, 1892, p. 62, pi. 1, fig. 14.

See remarks, + p. 427 .Locality : Nos. 2, 10, 17, 19, 22, 23, 25,
38, 39, 43, 44.

204 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC

Lagena invaginata sp. nov. (PL 18, fig. 13).

Test slightly carinate ; oral end protruding and arched ;
orifice a narrow slit, perhaps barred. The front highly convex ;
the back flat, with a large concave recess at the base. The
entosolenian tube long and bent to one side. Twenty-one
examples occur. Locality : Nos. 38, 41, 42 ; chiefly at No. 42.

Lagena reniformis sp. nov. (PI. 18, fig. 14).

The test reminds one of a kidney bean in shape ; the orifice is
situated on one side of the median line. The entosolenian tube
is long and attached. A few of the specimens are not nearly so
wide in relation to the height as the one figured. Locality :
About sixteen at No. 44. It occurs also at several other
stations.

Lagena reniformis sp. nov. var. (PI. 18, fig. 15).

I am treating this as a variation of the above. I believe the
orifice is composed of a series of pores, at any rate it is exceed-
ingly narrow. There are two other tests along with it, in which
the width is about equal to the height, but I think they belong
to the same variety. Locality : Uncertain.

Lagena reniformis sp. nov. var. spinigera (PI. 18, fig. 16).

The test is compressed, and the two spines, one on either side,
project upwards. The orifice is slightly sunk, and the tube is
long and attached, reaching almost round the shell. Two
specimens only found. Locality : Nos. 29, 44.

Lagena sp. incerfc. (PI. 18, fig. 17).

Probably this is only L. marginata in a contorted condition.
The test is carinate, compressed and twisted. Two occur.
Locality : Both at No. 15 ; or one at No. 1 and the other at
No. 15.

Lagena lagenoides Williamson sp. var. (PI. 18, fig. 18).

The test is elongate, not much compressed, and bicarinate.
Aperture fissurine. The keels, which only project slightly, are
tubulated.

I take this to be an elongate variety of L. lagenoides, William-
son sp., pi. 17, fig. 1. Three occur. Locality : No. 40.

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 205

Lagena staphyllearia Sch wager sp. var. (PI. 18, fig. 19).

Test compressed (lower part angular in outline) with five very
small protuberances arranged, as shown in the drawing, on the
edge of the shell. The entosolenian tube starts straight and
then bends towards the back of the test. Only four occur, and
they vary a little in outline. Locality : Nos. 3, 11.

Lagena sp. incert. (PI. 18, fig. 21).

I have only made an outline drawing of this form, because I
am not sure what its natural condition may be. The test
is compressed, and nearly all the examples are covered with
shell-growth, which has a sugary appearance. The colour is
a light cream. In those that are partially free from this in-
crustation, the test appears to be more or less in a hispid
condition. The carina, starting at the orifice, often ends abruptly,
as show r n in the illustration, but sometimes it gradually diminishes
until it is lost about half-way down the test. Two or more
spines adorn the base. It may be a compressed form of L. hispida.
Locality : Nos. 23, 29, 39, 40, 41.

Lagena sp. incert, (PI. 18, fig. 22).

I am puzzled with this form, not knowing whether to treat it
as L. marginata in which the keel has split, thus forming two
long loops, one on either side of the test ; or, as L. auriculata in
which the loops extend almost to the neck. It will be noticed
that the loops are quite separate at the base. Three occur. The
specimens are mixed with those of another form. Locality : One,
must have been found at No. 43 or No. 44.

? Lagena sp. (PL 18, figs. 23, 24).

I believe this to be a foraminifer, but it is very doubtful if it
be a Lagena. There was a small test, on the same square, which
had every appearance of being the initial chamber of the same
species. Unfortunately, in using a high-power lens for examina-
tion, I accidentally crushed the specimen ; but I bad previously
made an outline drawing of it, see pi. 18, fig. 24.

The large test, pi. 18, fig. 23, is not compressed. The orifice is
a rosette in form, and the upper part of the test is covered with
a raised irregular mesh. Rows of tubular projections run at

206 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

intervals across the test. It being a solitary example I do not
care to make a section of it, but probably it would reveal a series
of chambers. As Mr. Thornhill has placed it among the Lagena,
and it is such an interesting object, I cannot resist the oppor-
tunity of figuring it. It is opaque, but the single-chambered
specimen was quite transparent. Locality : No. 42.

Lagena maculata sp. nov. (PI. 18, fig. 25).

I was unable, for various reasons, to make out the nature of
this interesting species, so submitted the test to Mr. Earland, and
he has kindly sent me the following description of it :

"The shell appears to consist of two, probably three layers.
An inner test which is covered with a raised hexagonal outline
pattern, like network over a ball, and this in turn is covered
with an extremely thin outer test. This latter may be merely
chitinous or membranous ; it is sufficiently thin to show diffrac-
tion spectra. "Where this outer layer is stretched over the raised
pattern it is depressed in a rounded fashion, as though it had
been pressed down with the tip of the finger into the hexagonal
cavity beneath."

A solitary example. It belongs to the Waterwitch set of
Lagenae. Test not compressed.

Locality : No. 13. Station 238, Lat, 12"44' S., Long. 179*09' W.
(1,050 fms.).

Lagena marginata Walker and Boys var. ventricosa Silvestri.

Lagena ventricosa Silvestri, 1903-1904, Accad. Reale delle Scienze
di Torino, p. 10, figs. 6 a-e.

This seems to me simply a stout form of L. marginata. There
are eleven large specimens, but the carina is carried a little
farther up the test. Three of the tests are nearly round in
section. Examples moderately compressed, with orifice of the
same character, I have placed with L. marginata. Locality :
Nos. 5, 15.

[Mr. Henry Sidebottom has decided to make a type -slide of the
species described in his two papers as an index to the collection
of Lagenae. The collection will then be presented to the British
Museum (Natural; History), South Kensington, under the title,
<l The Thornhill Collection of Lagenae (South-West Pacific)."

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 207

DESCRIPTION OF PLATES.

Figs.

1-3.

L.

4.

L.

5,6.

L.

7,8.

L.

9,10.

L.

11.

L.

12, 13.

L.

1-1.

L.

15.

L.

16.

L.

17.

L.

18, 19.

L.

20.

L.

21.

L.

22.

L.

23.

L.

24, 25.

L.

26.

L.

27.

L.

28.

L.

29.

L.

30.

L.

31.

L.

32.

L.

Q D

-DO.

L.

Plate 15.

glohosa Montagu sp., x 50

apiculata Reuss sp., x 25

longispina Brady, x 50

botelliformis Brady, x 50

laevis Montagu sp., x 50

aspera Beuss, x 50

aspera Reuss, x 75

rudis Reuss, x 50

hispida Reuss, x 50 .

hispida Reuss var. tuhulata Sidebottom, x 50

striata d'Orbigny sp., x 75 .

costata Williamson sp., x 75

acuticosta Reuss, x 50

hexagona Williamson sp., x 50

hexagona Williamson sp., x 115

hexagona Williamson, sp., compress

X 115

sulcata Walker and Jacob sp., x 50

ph<migera Brady, x 50

semilineata Wright, x 50 .

crenata Parker and Jones, var. x 50

Thomhitti Sidebottom, x 75

stettigera Brady var. eccentrica Sidebottom, x 50

stelligera Brady var. eccentrica Sidebottom, com

pressed variety, x 50 .
foveolata Reuss (?), var. paradoxa Sidebottom, x 75
Hertv:igiana Brady, X 50 .

ed varietv

Page

164

165

165

166

166

167

167

168

168

168

169

170

171

171

171

171
172
173
173
174
174
175

175

177
178

208 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Plate 16.

Figs.

1. L. splenclida sp. nov., x 75

2, 3. Diagrams of decoration ......

4. L. spumosa Millett, x 75 . . .

5. L. laevigata Reuss sp., x 115

6. L. laevigata Keuss sp. var. virgulata Sidebottom, x 50

7. L. acuta Reuss sp. x 25 . . .

8. L. acuta Keuss sp. var., X 50 .

9. L. lucida Williamson sp., X 50
10-13. L. fasciata Egger sp., X 50

14. L. fasciata Egger sp. var. carinata Sidebottom, X 25

15, 16. L. fasciata Egger sp. var. carinata Sidebottom, x 50

17. L. marginata Walker and Boys, x 50

18. L. marginata Walker and Boys, x 75,

form . . .

19. 20. L. marginata W T alker and Boys, x 75

21. L. compresso-marginata Fornasini, x 75

22. L. marginata Walker and Boys, var.

Chapman, x 25 .

23. 24. L. marginato -perforata Seguenza, x 50
25. L. marginato-perforata Seguenza, x 75
26-28. L. lagenoides Williamson sp., x 50 .
29. L. lagenoides Williamson sp., x 75 .

Trifacial

catenulosa

Page

178

178

179

181

181

182

182'

183

183

184

184

186-

186.
186
187

187
189
189
190
190

HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 209'

Plate 17.

Figs.

1. L. lagenoides Williamson sp., x 75 .

2. L. lagenoides Williamson sp. var. nov. duplicate/,, X 75

3. L.formosa Schwager, x 50
4-7. L.formosa Schwager, x 75

8. L. formosa Schwager var., x 75

9. L. Orbignyana Seguenza sp., x 75

10. L. Orbignyana Seguenza sp., x 50

11. L. Orbignyana Seguenza sp., X 75

12. L. Orbignyana Seguenza sp. var. lacunata Burrows

and Holland, x 50

1 3. L. Orbignyana Seguenza sp. var. pulcheUa Brady, X 75

14. L. Orbignyana Seguenza sp.var. clathrata, Brady, x 75

15. L. Orbignyana Seguenza sp. var., x 75

16. 17. L. bicarinata Terquem sp., x 50

18. L. bicarinata Terquem sp., x 75

19. L. bicarinata Terquem sp., x 75

20. L. bicarinata Terquem sp., x 75

21. L. auricidata Brady, x 50

22. L. auricalata Bradv, x 75

Page

190

191

191

191

192

194

194

194

194

195

196

196-

197

197

197

197

198

19&

'210 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC.

Plate 18.

Figs.

1. L. auriculata Brady, x 75

2, 3. L. auriculata Brady var. nov. caudata, x 25 .

4. L. auriculata Brady var. nov. circumcincta, X 115

5. L. auriculata Brady var. nov. clvpeata, x 115.

6. L. auriculata Brady var., x 75

7. L. auriculata Brady var. duplicata Sidebottom, x 25

8. L. auriculata Brady var. duplicata Sidebottom, x 50

9. L. fimbriata Brady, x 75

10. L. fimbriata Brady var. nov. duplicata, x 75

11. L. alveolata Brady, x 50.

12. L. alveolata Brady, x 75

13. L. invaginata sp. nov., x 115 .

14. L. reniformis sp. nov., X 75

15. L. reniformis sp. nov. var., x 75

16. L. reniformis sp. nov. var. spinigera, X 7

17. Lagena sp. incert., x 75 .

18. L. lagenoides Williamson sp. var., x 50

19. L. staphyllearia Sch wager sp. var., x 75

20. L. squamoso-alata Brady, x 75

21. Lagena sp. incert., x 75 .

22. Lagena sp. incert., x 50 .

23. 24. (?) Lagena sp., x 50
2?. L. maculata sp. nov., x 75

Page

198
199
199
199
199
200
200
201
201
202
202
204
204
204
204
204
204
205
193
205
205
205
206

Journ. Quekett Microscopical Club, Scr. 2, Vol. XII., No. 73, Noc mber 1913.

Journ.Q.M.C.

Ser. 2, Vol. XII. PI. IS.

H.Sidebottoni del.ad nat.

West, Newman lith.

Laqenae of the South West Pacific Ocean.

"d

Jour n. O.M.C.

Sep. 2, Vol. XII. PL 16.

A l

6a

V

C

H.Side~bottom del.adn.at.

We s t .Newman

Lagenae of the South West Pacific Ocean.

Joum. Q.M.C.

Ser. 2, Vol. XII, PI. 17.

.

8a

. ?2

* ;-;:. ^\
':-V- X--

v

il&K 9

10a

b

Y

Mi

,

. b

[

B

- -

H.StdebottOTn del. ad nat.

West,Newman lith.

Lagenae of the South West Pacific Ocesun.

Journ . Q.M.G.

Ser.2,Vol.XII,P1.18.

jeST?**^.

5a b

K

10a

=> ,

k

11

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13a

ms

!4a

H.Sidebotfcom del. ad na:

We s b, Ne wm ax.

Lagenae of the South West Pacific Ocean.

211

GASTROTRICHA.

By James Murray, F.R.S.E.

Communicated by D. J. Scourjield.
{Bead October 28th, 1913.)

Plate 19.

INTRODUCTION.

I have been reluctant to attempt an introduction to the study
of the Gastrotricha, since my knowledge of the group is by no
means profound, and such as it is has been only recently acquired.
Jt is a group which has now reached such dimensions that it is
desirable there should be in the English language some sort of
synopsis of our present knowledge, and as there appears to be no
one else in the field to supply this want, I shall here do the best
I can.

The main part of this paper is an annotated bibliography,
which I hope will save students much of the trouble I have had.
It is difficult to hit a just mean between giving too much and tco
little. If too comprehensive and not annotated, a bibliography
rather hinders than helps by making the mass of works to be
consulted seem too great. A work is judged by its title to be one
that must be consulted, and after much labour is found to be of
no importance. I had a long search for a new genus and species,
Gastrochaeta ciliata, described by Grimm, before I found that the
name occurred in a mere list, in Russian, without a figure,
and that in a footnote all the comparison made was with species
of Desmoscolex, which belongs to a quite different group of
worms (25).

If the bibliography is too condensed the student is always
liable to suspect that a work omitted from it has not come to the
knowledge of the compiler. Such things frequently happen. I
have here tried to keep a proper balance. All important

212 J. MURRAY ON GASTROTRICHA.

general, biological and systematic works known to me are
included, as well as any really important faunistic studies.
Every work is given in which new species, or supposed new
species, or groups of higher value are described. The systematic
student wants these principally. There are omitted all merely
popular accounts, all trifling faunistic studies (records usually of
doubtful value), all references in textbooks of zoology which
contain nothing fresh, pronouncements on systematic position,
which are mostly only opinions not backed by personal knowledge
of the animals.

Monographists and close students of distribution will require
more than this bibliography contains, but they will be able to
get it for themselves.

It is unfortunate that the Gastrotricha, which include those
old familiar friends of the students of pond life Chaetonotas
larus and Ichthydium podura have no popular name. Gosse's
proposed name of " hairy-backed animalcules " is entirely un-
suitable, since some of the genera are not hairy-backed
[Ichthydium, Lepidoderma). I confess I am unable to suggest
any appropriate name. The name suggested by the scientific
term for the whole group, which embodies almost the only
character which they all possess, is unsuitable for popular use_
The Gastrotricha are not animals which can be named off-
hand. The days when we found Chaetonotus larus and
Ichthydium podura, occasionally varied by C. maximus, on all our
pond- life excursions are over. There are a host of Chaetonoti
which have contributed to the records of 0. larus. These species-
are all alike to a casual glance, but are distinguished by minute
characters the possession of small branches by certain of the
bristles, the form of the minute scales which bear the bristles r
etc. Some of these are so delicate that a high power and an
oil-immersion lens would be needed for their certain deter-
mination. This is impossible to apply to a living and lively
Chaetonotus, and as to killing the creature merely in order to
find out its name, well a philosophic naturalist might prefer-
to remain ignorant. To destroy this marvellous little living
gem simply to know how to label it ; is it worth while 1

Now we students of microscopic life cannot pretend to be
squeamish ; we have learned to kill lightly ; every time we clean,
a cover-glass we annihilate a world. But when it comes to

J. MURRAY ON GASTROTRICHA. 213

deliberately ending the individual life which we have before our
eves, intelligent, and surely innocent, I confess that, old and
hardened as I am at the game, I feel guilty of murder.
My ideal is that realised by Mr. Bryce, with his " zoo " of
Rotifera, all kept alive in cells, visited again and again for weeks
and months, till they become old familiar friends, each known by
sight and name : where a death in the family is regretted, and
the beasties, in fact, reach a ripeness of old age which must be
rare under natural conditions.

I wish to thank Mr. Rousselet and Mr. Bryce for the assistance
they have given me in preparing this paper, by lending me
specimens and books, and Mr. Harring for bibliographical refer-
ences and extracts from works which I had not seen.

Form axd Structure.

AH Gastrotricha are built on a very uniform plan. Most of
them have a roundish, often 3- or 5-lobed head, a more or less
distinct neck and a slightly expanded body, diminishing pos-
teriorly to a usually forked, but sometimes undivided extremity
{tail or foot). The principal external features are : the tubular
mouth, certain sensory hairs on the head, various forms of scales
and hairs clothing the dorsal surface. The ventral surface is
traversed for its whole length by two bands of vibratile cilia, by
which the creatures can creep in the manner of an Adineta, and
sometimes even, apparently, swim. A few possess clear bodies
which have been supposed to be eyes.

Of the internal structure I shall say little, as I have given it
little study, and I can only quote from authors who have studied
it. The animals are on about the same plane as the Rotifera for
complexit}', but they look much simpler fewer organs are readily
visible. A casual examination shows only a thick skin and the
body cavity, through which passes the simple alimentary canal ;
the slender oesophagus passing through an oblong muscular
pharynx ; the expanded stomach (or intestine) occupying most
of the body cavity. There is a small intestine, from which the
anus opens at the base of the furea, on the dorsal side.

Several naturalists have detected a water-vascular system
somewhat like that of the Rotifera, but according to Zelinka
it differs in many points. The canals are much convoluted,

214 J. MURRAY ON GASTROTRICHA.

and possess only one vibrating cell corresponding to the series-
of flame-cells of Rotifera ; there is no contractile vesicle, and the
canals open independently on the ventral side and have no
connection with the intestine.

While the eggs are frequently conspicuous, and their develop-
ment may be conveniently studied, the sexual system is little
known. Zelinka distinguishes paired ovaries. If the supposed
male organs are such the Gastrotricha are hermaphrodite.

Zelinka recognises in the alimentary canal the following parts :
mouth, oesophagus, stomach, intestine with rectum and anus.

There is a well-developed muscular system, and the brain and
nervous system are similar to those of the Rotifera.

Haunts and Habits.

The Gastrotricha are found mainly in ponds, oftenest among
the bottom sediment or vegetation. They rarely occur on mosses,
except the permanently moist aquatic kinds. A few (at least
one species, C. marinus) live in the sea.

They are much less common, even in ponds, than the
Rotifers and Water-bears. You cannot go out to collect
assured of getting some you must trust to casual occurrences
when studying other things.

There are no special methods of collecting them. They will
occur among your Rotifers, but not if you collect in clear, open
water. Perhaps the likeliest means to obtain some is to wash
aquatic weeds Myriophyllum, Fontinalis, Lemna, etc.

If you wish to preserve them it can easily be done. As they
are not contractile, they can be killed without previously
narcotising by osmic acid, when they retain the natural shape..
They can be mounted in fluid cells by Rousselet's method, but
formalin of the strength used for Rotifers is not a suitable
medium, as it produces subsequent distortion. Some better
medium has yet to be found.

They appear to have only one habit, that of eating. They
ar; always in motion, some slowly, some quickly, and always
seem to be nosing for food. Yet they are not greedy eaters, but
pick daintily here and there. As they creep along over the weeds
they give the impression of active intelligence proportioned to-
their needs.

j. murray on gastrotricha. 21>

Historical Sketch.

As a history would be little more than the bibliography
arranged chronologically, it need not take up much space.

So far as my knowledge goes, the first notice of an animal of
this order is by Joblot (32) 1718, who figures (Plate 10, fig. 22)
his " poisson a la tete en trefie," which is the animal now known
as Ichthydium.

Corti 1774 (10) speaks of an " animaluzzo molle," and figures
it, which Ehrenberg thinks may be a Chaetonotus.

Eichhorn 1781 (20) figures (Plate 2, fig. R) what may have
been a Chaetonotus.

These were the pioneers, who bestowed no binomial desig-
nations, but, before either Eichhorn or Corti, Miiller had in 1773
(42) given three such names, the first, Cercaria podura, still
persisting as Ichthydium podura.

Many of the pre-Ehrenbergians bestowed various names on
Gastrotrichs, usually only in attempts to classify, not describing
supposed new species : Schrank 1776 (53) Brachionvs pilosus ;
Lamarck 1815 (34) Furcocerca ; Bory 1824 (3) Leucophra, 1826
(4) Diceratella ; Ehrenberg's first attempt, Hemprich and Ehren-
berg 1828 (29) was Diurella podura (= Ichthydium).

Ehrenberg did not notably advance the knowledge of this
order, but he described two new species besides others, which are
not now recognised as Gastrotrichs.

After Ehrenberg came a rather barren period leading on to
quite modern times: Dujardin 1841 (16), Gosse 1851 (23) and

1864 (24), Schultze 1853 (55), Schmarda 1861 (52), Metchnikoff

1865 (41), Tatem 1867 (61). The only works of any importance
in this period are Gosse's and Metchnikoff's.

Modern times may be said to begin with Daday in 1882 (11),
and the principal workers have been Daday 1897 (12), 1905 (14),
1910 (15); Collin 1897 (8), 1912 (9); Stokes 1887 (57) (59);
Zelinka 1889 (71); Voigt 1904 (68); Lauterborn 1893 (35);
Griinspan 1908 (26); Marcolengo (40) (72).

Classification.

The classification of the Gastrotricha is in an unsatisfactory
condition. They are difficult animals to classify. I sympathise-
with the efforts authors have made to introduce order into the-

216 J. MURRAY ON GASTROTRICHA.

group, and will not attempt to modify the generic arrangement,
beyond shifting about some of the species. I am not qualified to
deal with the question, but as some little assistance to students
1 shall point out some apparent shortcomings of the prevailing
classification.

The three fork-tailed genera, Ichthydium, Chaetonotus and
Lepidoderma, are separated on very slight characters, as Stokes
(57) recognised in " lumping " them all together. Ichthydium
has neither plates nor dorsal bristles ; Lepidoderma has scales,
but is supposed to have no bristles ; Chaetonotus has bristles,
and may have scales. So if an Ichthydium or a Lepidoderma
possesses any dorsal bristles it becomes a Chaetonotus. How
many bristles are necessary ? Some so-called Lepidoderma have
a very few bristles. L. loricatus, Stokes, has no bristles, while
a variety has four near the tail.

Authors have made the matter worse by entirely disregarding
the generic definitions, even those made by themselves. Thus
Zelinka's Lepidoderma was instituted first to contain Dujardin's
C. squammatus, which was described in these terms, " Revetu
en dessus de poils courts, elargis en maniere d'ecailles pointues
regulierement imbriquees," and which is thus a true Chaetonotus,
following Zelinka's own definition.

The possession or not of scaly armour is surely itself more
important than the presence or not of bristles on the scales,
but the character has not been used in classification quite
rightly, for the scales are after all only the enlarged bases of
the hairs, and there is every gradation from a slightly enlarged
insertion to large imbricated scales.

Authors have further confused matters by professing to identify
a,s the species of the earlier authors animals which are quite
different from their descriptions and figures. This is pernicious,
as the practice nullifies the meaning of language, however
precisely used. It may be admitted that the descriptions of
Muller and Ehrenberg are insufficient to distinguish their species
from the numerous similar species now recognised. But the
species must either be dropped as " insufficiently described," or,
if we profess to recognise them, it must be in animals possessing
at least the characters ascribed to them by their discoverers.

Ehrenberg has many faults, among which I reckon not
least the insufficiency of his descriptions. Frequently these

J. MURRAY ON GASTROTRICHA. 217

contain no single distinctive character, and if it were not for
his figures their recognition would be impossible. But he was
not a slipshod observer, and when he happens to mention a
distinctive feature I have no doubt the animal observed possessed
it. Thus when he distinguishes C. maximus from C. larus by
its dorsal bristles of equal length, we must give him the credit
of supposing that his animal looked like that, unless naturalists
agree that no such animal exists a difficult thing to prove.
There are species with the dorsal bristles approximately of equal
length, and so Gosse is not justified in identifying as C. maximus
a species having the posterior bristles much longer.

In the separation into larger groups, sub-orders, or families,
the group has been equally unfortunate. The classification by
Fraulein Griinspan (26) recognises three sub-orders :

Suborder I. Euwhthtdina, having a forked tail.

II. Pseudopodisa, having an apparently forked tail.
III. Apodixa, without a forked tail.

55
55

I am unable to grasp the distinction between a forked tail and
an apparently forked tail, and the Apodina include one genus
(Stylochaeta) which has a forked tail ; minute certainly, but is a
small tail not a tail ?

Zelinka's (71) classification is consistent, but the more puzzling
genera were not discovered when he wrote. He recognises two
sub-orders, and, I should suppose, three families, though he only
names two :

I. Sub-order : Euichthydina, having a "furca."

1. Family Ichthydidae, without bristles.
Genera Ichthydiu'ni and Lepidoderma.

2. Family Chaetonotidae, with bristles.
Genera Chaetonotus and Chaetura,

II. Sub-order: Apodina, without a "furca."
Genera Dasydytes and Gossea.

Collin (9) follows Zelinka's classification, naming the family
Dasydytidae, which includes all the Apodina, and allocating
all the genera described since Zelinka's work to places in the
three families.

All this is very unsatisfactory. The anomalies of these systems
I have pointed out as exemplified in that of Fraulein Griinspan.

Journ. Q. M. C., Series II. No. 73. 15

218 J. MURRAY ON GASTROTRICHA.

I have no better to offer, so I suggest that we leave classification
on broad lines till we know more, and classify in genera only.

These have also been badly handled. Ehrenberg's two genera,
Ichthydium and Chaetonotus, will serve as a beginning of classi-
fication till we find something better. The distinction between
hairy and smooth is not important, and in many genera of
animals both types occur -e.g. Macrobiotus among Tardigrada,
but among Gastrotricha, if we are to have divisions at all,
we must be satisfied with very trivial characters. Miiller's
Cercaria poduva, which became the type of Ichthydium, was
probably a composite diagnosis, as some of his figures show
bristles. I have shown the unsatisfactory treatment of his genus
Lepidoderma by Zelinka, but, if his generic characters were
regarded in allotting species to it, it might serve as a temporary
artificial genus till we see our way out of the muddle.

Ehrenberg's obsession for symmetry in classification led to
many obviously false associations of species, and tyrannised over
naturalists till a late period, even as late as 1864 affecting
Gosse. It is curious now to regard the genera once included
in the Gastrotricha Ptygura, Glenojihora and to think that
Sacculus and Taphrocampa were originally described by Gosse
as Gastrotrichs.

Key to the Genera.

A. Without a furca.

1. Body with long bristles .... Dasydytes.

2. Body without long bristles . Anacanthoderma.

3. Head with antennae . Gossea (G. antennigera).

B. Furca minute or obscure.

4. Furca minute, large barbed bristles . Stylochaeta.

5. Furca obscure, short ..... Setopus.

6. Head with antennae . . . Gossea (two species).

C. Furca conspicuous, body with bristles.

7. Furca simple, bristles pointed . . Chaetonotus.

8. Furca simple, bristles expanded at apex Aspidiophorus.

9. Furca twice furcate ..... Chaetura.

D. Furca conspicuous, body without bristles.

10. Body with scaly armour . . . Lepidoderma.

11. Body without scales .... Ichthydium.

J. MURRAY ON GASTROTRICHA. 219

Note. Anacanthoderma can hardly be separated from Dasy-
dytes, as the only species is described as having some bristles.
Aspidiophorus is a Chaetonotus, having the bristles enlarged at the
apex, scarcely a generic distinction, as those having enlarged
bases are not considered generically distinct. Gossea is usually
put in the Apodina, but Daday's two species possess the furca,
and Gosse's antenniger with its caudal bundles of setae may be
said to possess the homologue of the furca. Setopus primus
is scarcely distinguishable, even as a species, from Dasydytes
bisetosus Thomp., yet from the possession of a slight medial
depression at the posterior end it has technically a furca, and
becomes a distinct genus.

List of all Species which have been Described.

In alphabetical order, and under the original generic names,
with critical notes on synonymy and specific values.

1910. Anacanthoderma punctatum Marcolongo (40).

1902. A sp)idonotus paradoxus Yoigt. (65). Now a genus Aspidio-

phorus.
1865. Cephalidium longisetosum Met. (41). Is a Dasydytes.
1773. Cercaria podura Mull. (42). Now the type of Ichthydium

Ehr.
1887. Chaetonotus acanthodes Stokes (57).
1887. C. acanthophorus Stokes (57).

1903. C. arquatus Voigt. (67).
1832. C. breve Ehr. (16).
1889. C. brevispinosus Zel. (71).
1901. C. chuni Voigt. (64).

1887. C. concinnus Stokes (57). Is a Lejndoderma.

1910. C. decemsetosus Marco. (40).

1905. C. dubius Dad. (14).

1887. C. enormis Stokes (57).

1905. C. erinaceus Dad. (14).

1887. C.formosus Stokes (59).

18(54. C. gracilis Gosse (24).

1905. C. heterochaetus Dad. (14).

1910. C. hirsutus Marco. (40).

1865. C. hystrix Met. (41).

220 J. MURRAY ON GASTROTRICHA.

1910. G. larvides Marco. (40).

1902. C. linguaeformis Voigt. (66).

1867. G. longicaudatus Tatem (61). Is an Ichthydium.

1887. G. longisjnnosus Stokes (57).

1887. G. loricatus Stokes (57). Is a Lepidoderma.

1893. G. macracanthus Laut. (35). Is probably G. entzii

(Dad.).
1889. C. macrochaetus Zel. (71).

1904. G. mwrinus Giard. (22).

1832. G. maximus Ehr. (18). 1

1910. G. minimus Marco. (40).

1908. C. multispinosus Griin (26). Is C. tabnlatum Schm.
1901. G. nodicaudus Voigt. (63). Very like G. entzii (Dad.).
1910. C. nodifurca Marco. (40). Very like G. entzii (Dad.).
1887. G. octonarius Stokes (57).

1897. G. ornatus Dad. (12).

1910. C. paucisetosus Marco. (40).

1889. C. persetosus Zel. (71). j

1909. C. ploenensis Voigt. (69).

1905. C.pusillus Dad. (14). ]
1887. C. rhomboides Stokes (57). Is probably 0. entzii (Dad.).
1865. C. schidtzei Met. (41).

1901. C. serraticaudus Voigt. (63).

1889. C. similis Zel. (71). |

1909. C. simrothi Voigt- (69).

1887. C. spinifer Stokes (57). ]

1887. C. spinidosus Stokes (57).

1864. C. slackiae Gosse (24).
1841. C. squammatus Dnj. (16).

1902. C. snccinctus Voigt. (66).

1887. C. sulcatus Stokes (57). Is an Ichthydium.

1908. C. tenuis Griin. (26).

1902. C. uncinus Voigt. (66).

1908. C. zelinhai Griin. (26),

1865. Chaetura capricornia Met. (41).
1913. C. piscator Murray. (Described in this paper for first

time.)
1851. Dasydytes antenniger Gosse (23). Now the genus Gossea.
1891. D. bisetosus Thomp. (62).
i909. D. dubiiis Voigt. (69).

J. MURRAY ON GASTROTRICIIA. 221

1909. B.festhians Yoigt. (69).

1851. D. goniathrix Gosse (23).

1909. D. ornatus Voigt. (69).

1910. D. pa ucisetosus Marco. (40).
1887. D. saltitans Stokes (59).

1901. D, stylifer Yoigt. (64). Is a Stylochaeta.

1893. D. zelinkai Laut. (35). Seems to be D. goniathrix Gosse.

1886. Ichthydium bogdanovii Schim. (51). Is a Chaetonotus.

1905. /. crassum Dad. (14).

1908. /. cyclocephalum Griin. (26).

1882. /. entzii Dad. (11). Is a Chaetonotus.

1901. I.forcipatum Voigt. (64).

1861. I . jamaicense Schin. (52). Is a Chaetonotus.

1897. /. macrurum Collin. (8).

1865. /. ocellatum Met. (41).

1861. /. tabulatum Schm. (52). Is a Chaetonotus.

1908. /. tergestinum Griin. (26).

1905. Gossea fasciculata Dad. (14).

1905. G. pauciseta Dad. (14).

1897. Lepidoderma biroi Dad. (12). Is probably C. entzii (Dad.).

1905. L. elongatum Dad. (14). Is probably C. entzii (Dad.).

1910. L. hystrix Dad. (15). Is probably C. entzii (Dad.).

1890. Polyarthrafusiformis Spencer (56). Now genus Stylochaeta.

1908. Setopus primus Griin. (26). Scarcely differs from Dasydytes.

1776. Trichoda larus Mull. (43). Now Chaetonotus larus.

Identification of Species.

It was my ambition to accompany this paper by a key to all
the species hitherto described, so that the student might identify
them all, or at least know what characters they were supposed
to have. I found the task beyond my powers, for not only are
there a number of descriptions which I have been unable to
consult, but many of the diagnoses are such that to make use
of the characters given in them would be actually misleading.

This is especially true of negative characters. Certain species
are described as having the body covered with scales, others as
having some or all of the bristles barbed or with supplementary
points. It must not be assumed that species not thus character-
ised do not possess those characters. Both are structures

222 J. MURRAY ON GASTROTRICHA.

excessively difficult to see, and the authors of species may have
overlooked them.

There is no more definite character for distinguishing species
of Chaetonotus than the form of the dorsal plates, if one could
only see them, but nothing has astonished me more than the
utter invisibility of those plates, till some accident, such as finding
an empty skin or mutilated specimen, has revealed them.

As I have put some work into the preparation of this key, and
do not wish to throw it away, I have made some use of the
material by indicating for the genus Chaetonotus certain groups
of species characterised by the possession of some common
feature.

Chaetonotus.

Body covered by Plates or Scales.

G. acanthodes, acanthophorus, arquatus, brevispinosits, chuni,
entzii, erinaceus, heterochaetus, hystrix, larus, linguaeformis, macro-
chaetus, maximus, octonarius, ornatus, persetosus, ploenensis,
pusillus, schultzei, serraticaudits, similis, simrothi, spinifer, squam-
matus, succinctus, tabidatus, tenuis, uncinus, zelinkai.

Stated to have no Plates.
G. enormis, formosus.

Nothing said about Plates.

G. bogdanovii, dubius, gracilis, jamaicense, longispinosus,
marinus, slackiae, spi?iulosus.

With Cephalic Shield.

C. entzii, erinaceus, formosus, maximus, ornatus, persetosus,
pusillus, schultzei, tenuis, zelinkai. Not noted for the other
species.

Head not Lobed.

G. bogdanovii, dubius, jamaicense, marinus, ornatus, slackiae,

tabidatus.

Head Three-lobed.

G. brevispinosits, chuni, erinaceus, formosus, heterochaetus,
hystrix, larus, linquaeformis, macrochaetus, pusillus, schultzei,
serraticaudus.

j. murray on gastrotricha. 223

Head Five-lobed.

C. acanthophorus, arquatus, eno?"mis, gracilis, longispinosus,
maximus, octonarius, persetosus, ploenensis, similis, simrothi,
spinulosus, squammatus, succinclus, tenuis, uncinus, zelinkai.

All Bristles with Supplementary Points (Barbs).
C. chuni, erinaceus, hystrix, schultzei, similis, spinifer.

Some Bristles Barbed.

C. acanthophorus, enormis, heterochaetus, longispinosus, macro-
chaetus, octonarius, persetosus, spinulosus, zelinkai. All the
others are supposed to have simple unbranchecl bristles.

Having Series of Larger Thicker Bristles.

C. acanthodes, acanthophorus, bogdanovii, brevispinosus, dubius,
enormis, heterochaetus, longispinosus, macrochaetus, octonarius,
ornatus, ploenensis, persetosus, similis, spinifer, spinulosus, suc-
cinctus, tenuis, uncinus, zelinkai.

Posterior Bristles Progressively Longer (exclusive of
the larger bristles above noted).

C. arquatus, chuni, entzii, erinaceus, hystrix, larus, macro-
chaetus, ornatus, pusillus, schultzei, similis, tenuis, zelinkai.

Bristles equal or not Noticeably Longer Posteriorly.

C. brevispfinosus, dubius, formosus, gracilis, heterochaetus,
jamaicense, linquaeformis, marinus, maximus, serraticaudus, sim-
rothi, slackiae, squammatus, tabulatus.

Notes on Some Species I have Seen.

I have in some of my faunistic lists noted Chaetonotus larus
and Ichthydium podura, but these records have the same value
as nearly all such records i.e. none.

At various times I have made studies of species which I could
not identify with the assistance of the literature at my disposal.
After reviewing nearly all the literature, and taking all tha

224 J. MURRAY ON GASTROTRICHA.

diagnoses at their face value, it appears that several of these
species differ from any of those described in the works known
to me.

I would have dealt with these in the usual way and described
them as new species, but just as I was finishing this paper Mr.
Harring of Washington was good enough to call my attention
to a paper by Marcolongo which I had overlooked (40). In that
paper there are described a number of new species of Chaetonotus,
as well as a new family and genus.

Mr. Harring has kindly transcribed the descriptions, which
appear to be better than such things usually are, but as they
are unaccompanied by figures no certain identification is possible.
I consider all descriptions of animals in this group unaccompanied
by figures as insufficient, but we are promised figures in a forth-
coming work by the same author.

In the circumstances I have no alternative but to withdraw
my new species in the meantime, but there can be no harm in
figuring and describing them as animals I have actually seen.

Several of these are figured on the plate, in company with
others which I do nob suppose to be new species.

The species of Chaetura I can describe with an easy mind, as
no one since Metchnikoff has ever described a species of this
genus.

Ichthydium sp. (PL 19, fig. 23).

A graceful little animal, with very slender neck, deeply
trefoliate head and long furca. The branches of the furca
are close together at the base, and diverge, tapering to points.
No tactile setae are noted, but the animal probably had them.
Length about 130 fx.

Habitat. Amongst Sphaynum, Fort Augustus, Scotland, 1904.

It is a good deal like Joblot's " poisson a la tete faite en trefle,"
which some have identified as /. podura. But what was /. podura
like ? Various animals have been figured by authors under that
name, stout animals and thin animals, with long, slender furca
or with little blunt knobs. Usually they do not appear to have
gone back to Miiller, or even to Ehrenberg, to find what podura
was like. If they had they would have found it was like various
things. Miiller's podura possessed bristles (in some figures), and

J. MURRAY ON GASTROTRICHA. 225

so ought to go into Ehrenberg's genus Chaetonotus. Its furca
was somewhat like the animal I have figured. Ehrenberg's had
a different furca.

Lepidoderma sp. (PI. 10, fig. 29).

A very small animal, with five-lobed head, apparently
rhomboid scales, and a short furca with diverging branches.
Long, tactile setae on the head. Length, 50 to 60 /x.

The small size might lead to the supposition that the animal
is young. In the only instance in which I have seen a Gastrotrich
hatch out of the egg the young was of the full adult length of
the species. It had only to eat and fill out. From this I suppose
that Gastrotricha, like many Rotifera, do not grow appreciably
in length.

I say the scales are " apparently ' rhomboid, because the
regular double diagonal arrangement in rows might give rise
to this appearance although the scales were of some other
form.

Chaetonotus sp. (PI. 19, figs. SlaSlb).

Of medium size ; trunk oval, neck well marked, head slightly
elongated, five-lobed, without cephalic shield. Mouth nearly
terminal, with tuft of hairs.

The bristles on the head and neck are excessively short and
fine. At the front of the trunk they become abruptly longer
and thicker (though still short) and progressively longer
posteriorly. Near the base of the furca there are some half-
dozen bristles longer and thicker than any others. None of the
bristles are barbed.

The scales from which the hairs spring are elongate hexagons,
with the angles so rounded off that they are almost oval. They
are arranged in regular diagonal rows, and are separated at
their bases by spaces about equal to the width of the scales.

The furca is short, the branches diverging, then converging
(enclosing a rhomboid place), obtuse.

No plates can be seen on the head or neck. It is the only
species I have seen in which the scales are visible and conspicuous
in a specimen in good condition.

Habitat. Scotland.

226 J. MURRAY ON GASTROTRICHA.

t

Chaetonotus entzii (Dad.)? (11) (PL 19, fig. 26).

A large animal, 250 to 300 jul and upwards in length. Head
obscurely 3-lobed, with two anterior processes, and two others at
posterior angles. Body long, nearly parallel-sided, covered with
apparently rhomboid scales, in diagonal rows, and fine short hairs,
gradually becoming longer posteriorly. Furca very long, nodose
(about twenty nodes in the length), widely divergent at base where
separated by small sulcus, less widely divergent above base.

Habitat. Pond in the Praca Republica, Rio de Janeiro, Brazil ;
several specimens.

About eight species of long-furcate nodose Gastrotrichs have
been described, which have all a suspiciously strong family likeness.
Some of these are certainly synonymous, their authors being
unaware of the existence of the other species. Daday, who is
responsible for the greater number of them, professes to draw
distinctions, but he is not very convincing, and moreover I have
found the animal here described to be extremely variable.

Daday first described entzii as an Ichthydium, although it had
the characters of Chaetonotus. Later he described similar forms
as Lepidoderma, although some of them at any rate did not fit his
genus. Some he compared with entzii and with rhomboides Stokes,
noting that some had not the spines on the head, some had the
furca hairy, others smooth, etc. I cannot pretend to sort oat all
of these here, but content myself with pointing out the family
resemblance.

Those I found in Rio had the hairs extremely variable, in some
very short, in others not visible at all. I could not doubt that
these were all one species, as I could see no other differences
whatever. The various species having long nodose furca will be
found noted in the list of all described species.

Chaetonotus sp. (PI. 19, fig. 30).

Large. Head short, 5-lobed, with cephalic shield, neck slightly
marked. Body clothed with simple hairs in about fifteen or
sixteen longitudinal rows, progressively longer posteriorly. Scales
like spear-heads, very like those of C. larus (fig. 9). The outline
of the body appears crenulate, with very prominent papillae in
the narrow part above the furca. About eight longer setae close

J. MURRAY ON GASTROTRICHA . 227

to the furca, springing from the papillae. Fnrca longish, widely
divergent, obtuse pointed.

Habitat. Praca Republica, Rio de Janeiro. The original larus
is probably not now recognisable, but modern authors have
defined it as an animal with scales as in fig. 9, and about eleven
longitudinal rows of them. This has more numerous rows. As
far as can be judged from the description without a figure, this
species is very like C. laroides Marco., but that is said to have the
scales truncate posteriorly.

It is to be noticed that these very destinctive scales are quite
invisible in living or well-preserved specimens. I have only
managed to see them in empty, partly shrivelled skins.

Chaetonotus sp. (PI. 19, fig. 34).

Of moderate size. Head obscurely 3-lobed, with large cephalic
shield. Body covered with long, widely out-curved bristles, all
barbed, in few rows (six seen in dorsal view) springing from
obscure but large hemispherical scales. Close to the furca nine
very long, recurved, barbed bristles, three dorsal, six lateral.
Branches of furca long, separated by sulcus at base, outcurved,
knobbed.

Habitat. Sydney and New Zealand ; a very similar form in
Rio, Brazil.

The most obvious character is the widely spreading bristles.
Even those nearest the cephalic shield are long, but they are
progressively longer posteriorly till near the furca, when a few
quite short bristles intervene between the longest dorsal bristles
and the special large ones at the furca.

Chaetonotus sp. (PI. 19, fig. 35).

Of moderate size, relatively broad and squat. Head rounded,
5-lobed. Neck well-marked, short. Trunk parallel-sided. Body
covered with apparently rhomboid scales, each bearing a short
spine or scale. Furca short, diverging, then converging (enclosing
a rhomboid space), the basal portion scaly, the apical portion
smooth. There are long tactile setae on the head.

The general form is like that of Ichthydium ocellatum Met.
[Lepidodei'ma ocellatum Zel.). I saw nothing like the eye-spots
ascribed to both those animals.

228 J. MURRAY ON GASTROTRICHA.

As there are no type specimens, and only MetchnikofTs descrip-
tion to go by, there is no justification for transferring his species
to the genus Lepidoderma, as Zelinka does. It is either an
Ichthydium Ehr. or insufficiently described and unrecognisable.

Zelinka's animal may be the one which I here figure. If so
it seems to me that the little triangular scales or spines are
homologous with the bristles of Chaetonotus, and not with the
scales of Lepidoderma, and so it should be placed in the former
genus.

Habitat. Summit of Ben Lawers, Scotland, among moss, 1905.

Chaetura piscator sp. now (PI. 19, fig. 33).

Specific characters. Small ; head elongate, egg-shaped, fringed
with long setae ; neck moderately constricted ; body spindle-
shaped ; each branch of furca forked, branches equal ; trunk
bearing at least four longitudinal series of fine bristles shaped like
fish-hooks, and some straight setae near the furca.

General description. Length 150 /x, head 50 /x long by 36 /x
wide, trunk 30 fx wide, branches of furca about 12 jx ; hooks
project about 15 fx above the surface.

The head is the widest part of the body. It is fringed by long
straight hairs or setae, and bears some larger movable setae which
appear to have a tactile function. The neck is slightly constricted,
but has a swelling. The dorsal hairs are shaped exactly like fish-
hooks, without their barbs. They spring out at nearly right
angles to the skin, curve round in the posterior direction, and
nearly touch the skin at their tips. I distinguished four rows
of them, but in dealing with such excessively fine structures
it is not well to state hard-and-fast numbers. Four of the
straight setae could be seen dorsally, close by the tail ; the four
branches of the furca are nearly equal, slightly curved, and have
blunt tips.

Technically this is a Chaetura, having the branches of the furca
furcate, although in MetchnikofTs type species, G. capricornia,
they are not properly furcate, but bear little branches on the
inner side. As in the type, the head is broader than the trunk
and there are stiff bristles over the tail. The fishhook-like setae
distinguish it from all other known Gastrotrichs.

Habitat. Amongst moss, Shetland Islands, 1906.

j. murray on gastrotricha. 229

Bibliography.

An asterisk * indicates works in which new species are described.

The works of any importance number scarcely more than a
dozen. They are Ehrenberg, 1838 (19); Gosse 1851 (23), and
1864 (24); Metcbnikoff 1865 (41); Stokes 1887 (57); Daday
1882 (11), 1901 (13), 1905 (14), 1910 (15); Zelinka 1889 (71);
Giard 1904 (22); Yoigt 1904 (68); Griinspan 1909 (26); Collin
1912 (9).

With these works the student will have everything he requires,
except a few descriptions of doubtful new species.

Ehrenberg, 1838, summarises the work of the pioneers, and
originates a classification. Fraulein Griinspan, 1909, gives the
fullest systematic account of the group. Zelinka, 1889, is far and
away the best work on the subject, being a painstaking and
minute study ; but much has been added to our knowledge since his
memoir appeared. Collin, 1912, is simply a compilation, but a
useful one. The others noted above are the principal systematic
works, containing descriptions of many species.

1. Archer, W. In Quart. Joum. Micr. ScL, 14, p. 106, 1874.

Exhibited at Dubl. Micr. Club, C. maximus, C. gracilis,
and D. antenniyer ; all found in Ireland. Note that the
last species can elevate and depress its antennae.

2. Barrois, T. Comptes rendus, July 1887. Trans, in Ann.

Mag. Nat. Hist., xx., p. 365, 1877.

A segmental worm, having the appearance of Ichthy-
dium, but differing much in structure. Probably related
to Hemidasys, Turbanella, Zelinkia, Philocyrtis, which are
not Gastrotricha.

3. Bory de St. Vincent. Encycl. method., Paris, 1824.

Furcocerca podura ( = Ichthydium) ; Zeucophrya larus
( = Chaetonotus).

4. Ibid. Essai des micr., 1826.

Diceratella larus ( = Chaeto?iotus).

5. Bryce, D. In letter to Fraulein Griinspan (vide 26, p. 228).

Records C. zelinkai for England and Scotland.

6. Butschli, O. Freilebende Nematoden u. d. Gattung Chae-

tonotus. Zeit. fur wiss. Zool., 26, pp. 385, 390, etc., 1876.
Classification and Anatomy. Good structural figures of
C. maximus and C. larus.

230 J. MURRAY ON GASTROTRICHA.

7. Claparede, E. Misc. zool. III. nouveau genre de Gastero-
triches. Ann. Sci. Nat., Ser. 5, vol. 8, p. 18, 1867.

Hemidasys agaso gen. et sp. nov. Not a Gastrotrich, I
think.

*8. Collin, A. Rot. Gastro u. Entoz. Deutsch Ost-Afrika, 4, p. 9,
1897.

/. macrurum sp. n. A somewhat meagre description,
from figure drawn by Stuhlman.

9. Ibid. Gastrotricha. In Susswasserfauna Deutschlands,
pp. 240-65, figs. 475-507.

A good account of thirty-two German species, with
many useful figures. No new species.
10. Corti. Osser. micr. sulla Tremetta, p. 89, PI. 2, 1774.

Ehrenberg thirks the " animaluzzo molle " may have
been C. maximus. I have not seen the work.
*11. Daday, E. Ichthydium entzii.

Termes. Fiiz., pp. 231-52, PI. 3, 1882.

New species ; full description and good figures. Seems
to be the first appearance of a much-described animal
which is almost certainly the same as Stokes' C. rhom-
boides, and is probably also Yoigt's C. nodicaudus
and Daday's own L. hystrix, L. elongatum and L. biroi,
as well as C. macracanthus Laut. I found the animal
in Rio de Janeiro, and noted that the dorsal hairs
vary greatly in length and may be absent, so that
the species is both Chaetonotus and Lepidoderma on
occasion !

*12. Ibid. Uj-Guineai Rotatoriak. Math. es. Termes. Ertes.,
vol. 15, pp. 145-48. (In Hungarian.) 1897.
New species C. orno.tus and L. biroi.

13. Ibid. Mikr. Siisswasserthiere aus Deutsch Neu-Guinea.
Termes. Filz., 24, 56 pp., 3 plates, 1901.

Description and figures of the two new species of his
previous paper (1897).

*14. Ibid. Susswasser-mikrofauna Paraguays. Zoologica, 18,
pp. 72-86, Pis. 5-6, 1905.

Eight new species I.crassum, L. elongatum, C.pusillus,
C. dubius, C. erinaceus, C. heterochaetus, G. fasciculata,
G. paaciseta.

J. MURRAY ON GASTROTRICHA. 231

*15. Ibid. Susswasser-mikrofauna Deutsch Ost-Afrikas. Zoo-
logica, 23, pp. 56-9, PI. 3, 1910.
New species L. hystrix.
*16. Dujardin, F. Hist. nat. des Zoophytes Infusoires, pp. 515-
69, PL 18, figs. 7-8, 1841.

New species C. squamniatus.
17. Ibid. Sur un petit animal marin (l'Echinodere). Ann. Sci.
Nat., Ser. 3, vol. 15, p. 158, PI. 3, 1851.
Once classed with the Gastrotricha.
*18. Ehrenberg, C. J. Organ, in d. Richtuny d. kleinsten Raumes,
2nd Part, Berlin, 1832.

Descriptions (perhaps not his earliest) of /. podura,
C. maximus, C. larus, C. breve.

19. Ibid. Die Infusionsthierchen, pp. 386-90, 1838.

Redescribes the same four species as in 1832.

20. Eichhorx, I. C. Naturgeschichte der kleinsten Wasserthiere,

p. 35, PI. 2, fig. r, 1781.
Probably a Chaetonotus.

21. Florentin, R. Faune des mers salees. Ann. Sci. Nat.

(Ser. 8), 10, p. 272, 1899.

Records Lepidoderma ocellatam from salt water.
*22. Giard, A. Faunule caracteristique des sables a Diatomees.
C. R. Soc. Biol, pp. 1061-5, 1904.

New species C. marinus. Also new genera Zelinkia
(sp. Z. plana) and Philocyrtis (sp. P. monotoides), which
are very doubtful Gastrotricha.
*23. Gosse, P. H. A Catalogue of Potifera found in Britain.
Ann. Mag. Nat. Hist., Ser. 2, vol. 8, p. 198, 1851.

New genus Dasydytes, and new species D. goniathrix
and D. antenniger ; no figures. Saccidus viridis described
as a Gastrotrich.
*24. Ibid. The hairy-backed Animalcnli. Intell. Obs., V.,
pp. 387-406, 2 plates, 1864.

New species C. slackiae, C. gracilis.
Taphrocampa new genus, described as a Gastrotrich.
25. Grimm, O. A. Fauna im baltischen Meere (is a German
rendering of the Russian title). Arb. d. St. Peter. Naff
Ges., 8, p. 107, 1877.

Gastrochaeta ciliata new genus and species. No figure
given. In a footnote he compares the animal with various

232 J. MURRAY ON GASTROTRICHA.

species of Desmoscolex, so it is probably not a true
Gastrotrich.
*26. Grunspan, Therese. Systematik cler Gastrotrichen. Zool.
Jahrb., pp. 214-56, 1908.

A comprehensive synopsis of all known species. Seventy
admitted species ; six new species and a new genus /. terges-
tinum, I. cyclocephalum, C. zelinkai (and var. gra.censis), C.
tenuis, C. midtispinosas, Setoptcs primus(gen. et sp. nov.).

27. Ibid. Die SUsswasser-Gastro-trichen Europas. Eine zusam-

menfassende Darstellung ihrer Anatomie, Biologie und Sys-
tematik. Ann. Biol. Lacustre, Bruxelles, vol. 4, pp. 21 1 365 ?
61 figs.

28. Hartog, M. Rotifera Gastrotricha and Kinorhynchia.

Cambridge Nat. Hist., vol. 2, p. 232, etc., 1896.

A good account and figures of seven known species.

29. Heinrich u. Ehrenberg. Symbolae physicae. Evertebrata.

I. Phytozoa, Plates. Berlin, 1828; text, 1831.

PI. I., fig. 11, Diurella podura (= Ichthydium).
*30. Hlava, S. Syst. Stell. v. Polyarthra fusiformis Spencer.
Zoo. Anz., 28, pp. 8-9, December 1904.

New genus Stylochaeta (sp. S. fusiformis Spencer).

31. Imhof, 0. Tiefseefauna SUsswasserbecken. Zoo. Anz., 8,

p. 325, 1885.

Found C. maximus as an abyssal species in lakes.

32. Joblot. Nouvelles Observations, p. 79, PI. 10, fig. 22, 1718.

" Poisson a la tete faite en trefle " ( = /. podura).

33. Kojevnikof, G. Faune de la mer Baltique orientale.

Congres intern. Zool. II., Moscow, pp. 132-57, 1892.
I have been unable to find this work.

34. Lamarck. Hist. nat. des Animaux sans vertebre, p. 447, 1850.

Furcocerca podura ( = Ichthydium).
*35. Lauterborn, R. Rot. -Fauna d. Rheins u. s. Altwasser.
Zool. Jahrb., 7, Syst., pp. 1^54-73, PI. 11, 1893.

New species Dasydytes zelinkai, C. mawacanihus . The
description shows D. zelinkai as a not very distinct variety
of D. goniathrix Gosse. No figure is given. C. macra-
canthus appears to be C. entzii Dad.
36. Ibid. Die sapropelische Lebewelt. Zoo. Anz., 24, pp. 50-55,
1901.

Dasydytes zelinkai (see previous paper).

J. MURRAY ON GASTROTRICHA. 233

37. Lucks, R. Linaugebiet micr.-Wasserbewohner. Jahrb. West-

preuss. Lehrver.f. Naturk., pp. 20-23 (1905), 1906.
List of eight known species in West Prussia.

38. Ibid. Neues aus d. Mikrofauna Westpreussens. Ber. West-

preuss. Bot.-Zool. Ver., 31, pp. 141-2, 1909.

Three additional known species in West Prussia.

39. Ludwig, K. TJ. d. Ordnung Gastrotrichs. Zeit. far iviss.

Zool., 26, pp. 219-25, 1875.

A general work, dealing with systematic position, etc.
List of thirteen known species.
*40. Marcolongo, I. Primo contributo alio studio dei Gastro-
trichi del lago-stagno craterico di Astroni. Monitore Zool.
Ital. Firenze, 21, pp. 315-18, 1910.

He gives no figures, but describes a new family
Anacanthodermidae, a new genus linacanthoderraa, and
eight new species Chaetonotus laroides, C. hirsutus, C.
minimus, C. nodifarca, C. decemsetosus, C. 2)aucisetosus,
Dasydytes imucisetosus, Anacanthoderma punctatum.

I have not seen this paper, but received these particulars

by favour of Mr. Harring, of Washington. (Vide No. 72.)

*41. Metchnikoff, E. Wenig-bekannte niedere Thierformen.

Zeit. fur wiss. Zool, 4, pp. 450-8, PI. 15, 1865. English

trans, in Journ. Jlicr. Sd. (N.S. 6), pp. 241-52, 1865.

New genera Chaetura (sp. capr worms), Cephalidium
(= Dasydytes) (sp. longisetosum). New species Ichthy-
dium oceUatum, C. hystrix, C schultzei.
*42. Muller, O. F. Verm. terr. etfluv., pp. 66 and 79, 1773.

New species Cercaria podura (= Ichthydiam), Trichoda
acarus and T. anas (both now = C. larus).
*43. Ibid. Prod. Zool. Dan., 1776.

Trichoda lai'us ( = Chaetonotus).

44. Ibid. Anim. infus.fluv. et marina, 1786.

Trichoda larus ( Chaetonotus).

45. Nitzsch. Infusorienkunde, 1817.

Enchelys podura ( = Ichthydium).

46. Norrikov, A. Y. K. sistematikie Gastrotiicha (Russian).

Triid. Obs. Ahklim. Moskau, 6, 1907, pp. 309-47, PI. 10.

I have not seen this paper, but Mr. Harring, who kindly
furnished the reference, says it is largely a translation of
Zelinka's paper (71) and contains little that is new.
Journ. Q. M. C., Series II. No. 73. 16

234 J. MURRAY ON GASTROTRICHA.

47. Parsons, F. A. In the Quekett Journal for 1896-7 there

occur some records of Gastrotricha found at the excursions
of the Club. I do not know who made the actual iden-
tifications, but the records are referred to in Mr. Parsons's
name by various authors.

48. Perrier, E. Traits de Zoologie, Fasc. 4, pp. 1534-9, figs.

1103-5, 1897.

A general account of six species, with some figures.

49. Perty, M. Kleinste Lebensfovmen dev Schweiz, p. 47, 1852.

A few remarks on the group and several known species.

50. Pritchard, A. History of Infusoria, 1861.

The earlier editions of Pritchard contain a few notes
after Ehrenberg. In 1861 there is a fair account of the
group.
*51. Schimkewitsch, W. M. Neue Species Ichthydium. Nachr.

K. Ges. Freunde d. Natuv., 50, 1886 (/. bogdanovii).
*52. Schmarda, L. K. Neue wivbellose Thieve, i. 2, 1861.

Describes two new species as Ichthydium /. jamaicense
and /. tabulatum which are technically Chaetonotus,
according to his own generic definition of Ichthydium.

53. Schrank, P. v. P. Beitvdge ficv Natuvgeschichte, 1776.

His Bvacliionus pilosus (Part III., PI. 4, fig. 32) is,
according to Dujardin (16, p. 570, footnote), Chaetonotus
lav us.

54. Ibid. Fauna Boica, hi., pp. 90-91, 1803.

Tvichoda lavus ( = Bvacliionus pilosus), T. anas.

55. Schultze, M. Ueber Chaetonotus mid Ichthydium Ehr.

Avcli. f. Anat. u. Phys., vi., pp. 241-54.

New genus Tuvbanella, which I believe is not a
Gastrotrich.
*56. Spencer. On a new Rotifer, Polyavthva fusifovmis.

This is a Gastrotrich, since made the type of a new
genus, Stylochaeta, by Hlava (30). J. Q. M. C, 1890, p. 59.
*57. Stokes, A. C. Observations on Chaetonotus. The Micro-
scope (American), vol. 7, two parts, January and February,
1887, pp. 1-9, PI. 1 ; pp. 33-43, PI. 2.

One of the most considerable works on the group, in
which a great many new species are described. They are
all regarded as Chaetonotus, the earlier generic distinctions
not being admitted.

J. MURRAY OX GASTROTRICHA. 235

New species 0. sulcatus, C. concinnus, C. loricatus,
C. rhomboides, C. spinifer, C. acanthodes, C. octonarius,
C. spinulosus, C. longispinosus, C. enormis, C. acantho-
jjhorus.

Apparently good figures are given of all of these species,
and of species of other authors, but Stokes claims indul-
gence for inaccuracies in all his figures.
58. Ibid. Observations sur les Chaetonotus. Journ. de Microg.,
II, 3 parts, February, April, December, 1887, pp. 77-84,
150-3, 560-6, PI. 1 and 2.

Simply a translation of the American paper, with the
same plates.
*59. Ibid. Observation on a new Dasydytes and a new
Chaetonotus. The Microscope, vol. 7, pp. 261-5, 1 PI., 1887.
New species D. saltitans, C. formosus.
60. Ibid. Observations sur les Chaetonotus et les Dasydytes.
Journ. de Microg., 12, 2 parts, January, 1888.
A translation of the preceding paper.
*61. Tatem, T. G. New Species of Microscopic Animals. Quart.
Journ. of Micr. Sci., N.S. 7, pp. 251-2, 1867.
New species Chaetonotus longicaudatus.
*62. Thompson, P. G. A new species of Dasydytes. Science
Gossip, No. 319, 1891.
New species D. bisetosus.
*63. Yoigt, M. Bisher unbekannte Siisswasserorganismen.
Zool. Anz., xxiv., No. 640, pp. 191-4, 1901.

New species Chaetonotus serraticaadus, C. nodicaudus.
*64. Ibid. Unbesehriebene ' Organ. Plon. Gewassern. Zool.
Anz., xxv., No. 660, pp. 35-9, 1901.

New species Ichthydium forcipatum, Chaetonotus- chuni,
Dasydytes stylifer.
*65. Ibid. Rot. u. Gast. d. Umgebung v. Plon. Zool. Anz., xxv.,
No. 692, pp. 673-81, 1902.

He names nine species as new, but gives no descriptions
or figures except of one. Eight of them had been de-
scribed in earlier papers. The nine names are Ichthydium
forcijxitum, Aspidonotus paradoxus (n. gen., n. sp.), Chae-
tonotus linguaeformis, C. nodicaudus, C. serraticaudus, C.
uncinus, C. succinctus, C. chuni, Dasydytes stylifer. He
describes Aspidonotus and (p. 681) figures one scale.

236 J. MURRAY ON GASTROTRICHA.

*66. Ibid. Drei neue Ohaetonotus-Arten a. Plon. Gew'assern.
Zool. Anz., xxv., No. 662, pp. 116-18, January, 1902.
New species C. linguaeformis, C. succinctus, C. uncinus.

*67. Ibid. Erne neue Gastrotrichenspecies (Chaetonotus arquatus)
aus dem Schlossparkteiche zu Plon. Forschber. Biol. Stat.
Plon., x., pp. 1-4, 1903.

68. Ibid. Rotatorien u. Gastrotrichen d. TJmgebung von Plon.
Ploner Forsch.-ber., xi., 180 pp., 1904.

He records twenty-three species and describes nine as
new, but these have been described in earlier papers. He
renames the genus he had called Aspidonotus, making it
Aspidiophorus, as he found that the former name was
preoccupied.

*69. Ibid. Nachtrag zur Gastrotrichen-Fauna Plons. Zool.
Anz., xxxiv., No. 24/25, pp. 717-22, 1909.

New species Chaetonotus ploenensis, C. simrothi, Dasy-
dytes dubius, D. festinans, D. ornatus.

70. Wagner, F. Der Organismus der Gastrotrichen. Biol.
Centralb., 3, No. 7/8, 1893.

71. Zelinka, C. Die Gastrotrichen. Zeit. f. iviss. Zool., 49,
pp. 299-476, PI. 11-15, 1889.

An important paper, the most careful and scientific
that has appeared on the subject. He gives a good and
full account of the anatomy, a good bibliography, and a
good resume of all the systematic work on the group,
quoting most of the authors' original descriptions. Some
previously described species escaped his notice, as Ichthy-
dium entzii Dad. Two new genera and four new species
are described. The genus Gossea is framed to contain
Gosse's Dasydytes antenniger, Lepidoderma for Dujardin's
Chaetonotus squammatus, with C. rhomboides Stokes,
Ichthydium ocellatum Metch., and C. concinnum Stokes.
Lepidoderma is an unfortunate genus, as the type species
(C. squammatus Duj.) is spiny and a true Chaetonotus. C.
rhomboides Stokes is usually spiny, and /. ocellatum Metch.
is not stated or figured by its discoverer to have scales.

The new species are Chaetonotus similis, C. brevi-
spinosus, C. Qiiacrochaetus, C. persetosus.

72. Marcolongo, Ines. I Gastrotrichi del lago-stagno craterico
di Astroni. Atti Ace. Sci. Fio. e Nat. Napoli, vol. 14.

J. MURRAY ON GASTROTRICHA. 237

Explanation of Plate 19.

Scale and hair of :
Fig. 1. G. macrochaetus Zel. (After Zelinka.)

55
?5
55
55
?5
55
55
55
55
55

55

55
55
55
55
55
?>
fl
55
55
)5
55

9

6'. hystrix Metsch.

3. C. si?nilis Zel. (After Zelinka.)

4. C. maximus Ehr. (After Zelinka.)

5. G. persetosus Zel. (After Zelinka.)

6. G. pusillus Dad. (After Daday.)

7. C heterochaetus Dad. (After Daday.)

8. C. schidtzei Metch. (After Zelinka.)

9. G. larus Miill. (After Ludwig.)
10. C. erinaceus Dad. (After Daday.)

11 a. G. succinctus Voigt, one of the long bristles. (After

Voigt.)
116. C. succinctus Yoigt, scale from posterior part. (After

Voigt.)

12. G. hystrix Metsch. (After Zelinka.)

13. C. nodicaudus Voigt. (After Voigt.)

14. Aspidiophor us paradoxus Voigt. (After Voigt.)

15. Lepidoderma ehngata Dad. (After Daday.)

16. C. brevispinosus Zel. (After Zelinka.)

17. C. arquatus Voigt. (After Voigt.)

18. G. simrothi Voigt. (After Voigt.)

19. G. zelinkai Grim. (After Griinspan.)

20. C. uncinus Voigt. (After Voigt.)

21. G. chuni Voigt. (After Voigt.)

22. C. linyuaeformis Voigt. (After Voigt.)

23. Ichthydium sp. (?).

24. Lepidoderma loricata Stokes. (After Stokes.)
25a. Dasydytes goniathrix Gosse. Drawn from nature.
256. D. goniathrix Gosse. A single seta.

26. C. entzii Dad. (?). Differs from Daday's in having the
furca without hairs.

27. Dasydytes bisetosus Thomp. Drawn from nature.
28a. Gossea antennigera Gosse. Drawn from nature.
286. G. antennigera Gosse. Scale and hair.

? , 29. Lepidoderma, very small species. Drawn from life.

238 J. MURRAY ON GASTROTRICHA.

Fig. 30. Chaetonotus sp. (?). Scales as in C. larus (fig. 9), but
rows more numerous.
31. Chaetonotus sp. (?). With very distinct rhomboid scales.
316. Chaetonotus sp. (?). Three of the scales.

32. Setopus primus Griin. (After Griinspan.)

33. Chaetura piscator sp. n.

34. Chaetonotus sp. (?). All hairs long, widely spreading.

35. Chaetonotus or Lepidoderma. Like the animal figured
by Zelinka as L. ocellatam Met., but I saw no
eyelike bodies. Metchnikoff did not describe his
animal as scaly.

,, 36. Scales of C. tenuis Griin. (After Griinspan.)

Journ. Qvekett Microscopical Club, Ser. 2, Vol. XII., No. 73, November 1913.

Ser. 2, Vol. XII., PI. 19.

J. Murray, del. adnat.

Gastrotricha.

239

NOTES

ON A NEW METHOD OF MEASURING THE
MAGNIFYING POWER OF A MICROSCOPE.

By Edward M. Nelson, F.R.M.S.

{Read June 2Wi, 1913.)

Many microscopists, at one time or another, will have experienced
some trouble about the determination of the combined magni-
fying powers of their objectives and eyepieces. Some never
measure them at all, and rely upon the manufacturer's catalogues
for the results. This is not very satisfactory, for neither
objectives nor eyepieces turn out to be at precisely their nominal
foci ; and if both these should happen to be either in excess or
deficit the actual magnifying power will differ considerably from
that given in the catalogue. Therefore it will be better for every
one to measure the magnifying powers of the lenses of their
microscope.

There are two well-known methods of doing this. The first,
and perhaps the simplest, is to employ a photomicrographic
camera to measure the magnified image of the stage micro-
meter when projected on to the ground glass at a distance of ten
inches. The second is to project the magnified image of the
stage micrometer, by means of some sort of a camera lucida, on to
a scale, distant ten inches as before.

All this appears delightfully simple, but w^hen examined more
carefully it is not really so. First, the photomicrographic-camera
method requires a dark room, or the measurement must be made
at night, and of course it is sure to happen that when the
camera is most wanted it is not available. This is just what has
occurred to me. My photomicrographic camera and stand, which

240 E. M. NELSON ON A NEW METHOD OF MEASURING THE

are large and heavy, are packed away ; it would take some
hours to unpack them, clear out a room for their reception,
bring them in and set them up, so I have to be content with
some other means of measuring magnifying powers.

The second method, viz. that of employing a camera lucida,
also appears to be very simple, and so it is when a Powell No. 1
stand is used, which has its optic axis ten inches from the table,
when inclined horizontally ; a Beale's neutral tint fitting on the
" capped" eyepieces answers perfectly some attention, however,
is necessary to regulate the illumination, both in the tube and on
the rule, otherwise the coincidences of the lines cannot be
observed. But suppose a continental eyepiece is used, what
then ? The Beale camera will not fit, and all the simplicity of
one's arrangements and apparatus fails. If the microscope is
not a Powell's No. 1, then it must be placed upon a box, and the
distance of the rule adjusted by means of other boxes, books,
etc. With a Continental microscope matters are no better. One
has the simplicity of the Abbe camera, with its cleverly planned
device for regulating the illumination of the stage micrometer
and of the rule, but suppose the eyepiece is of the positive com-
pensating type, what is to be done ? The camera will not fit
and cannot be used. There are other cameras, both of the right-
angled and of the oblique type ; some eyepieces they fit and
others they do not. These difficulties are not imaginary, for
I have experienced all of them at one time or another. The
apparatus I now use is the old-fashioned Wollaston's camera,
mounted on a table screw clamp. This can be used with every
kind of eyepiece ; it is, however, troublesome to work with, and
it requires some practice to obtain a coincidence of the scales
how anybody can execute a drawing with such an apparatus is,
to me, quite incomprehensible !

I have devised an entirely new method by which all these
worrying little troubles may be avoided. First, it is necessary
to determine the " constant " of the eyepiece with a given tube
length. This is easily done, and when done it should be recorded,
or better still engraved on the eyepiece tube. To find the
" constant " of an eyepiece with a given tube length, first
determine the combined magnifying power of that eyepiece on
the given tube length with any objective, say one of medium
power, sudh as a |-in. or J-in. or |%-in. focus. Secondly, measure

MAGNIFYING POWER OF A MICROSCOPE. 241

the exact diameter of the field by means of the stage micro-
meter. The product of these two quantities is the constant of
that eyepiece with the given tube length.

Example : objective -in., eyepiece compensating x 8, tube
length 170 mm., measured magnifying power 280 diams. :
measured field 0-023 in. Product is 6'44, which is the constant
of that eyepiece for 170-mm. tube.

The power of any other objective with this eyepiece and tube
length can be determined by merely measuring the diameter of its
field by the stage micrometer ; for the magnifying power will ob-
viously be the eyepiece constant divided by the diameter of the field.

Thus, the problem of measuring the combined magnifying
power is brought down to the bed-rock of simplicity. No camera,
no regulation of illumination, no ten inches to measure ; in brief,
nothing to do but to count the number of divisions of the stage
micrometer in a diameter of the field and then divide this into
the eyepiece constant.

Example 1. With the same x8 compensating eyepiece and

170-mm. tube a |--in. objective gave a diameter of field of

6-44
0*0165 in. The magnifying power therefore is r w = 390.

Example 2. With the same x 8 compensating eyepiece and

1 70-mm. tube a 1 J-in. objective gave a diameter of field of 0*185 in.

6-44

The magnifying power therefore is .... = 35.

The determination of the constant is scarcely any more trouble

than the measurement of the magnifying power of one objective,

and when once found need not be determined again ; it would

ndeed be most helpful if manufacturers would measure these

constants and engrave them upon the tubes of their eyepieces.

Obviously the diameter of the field can be measured while the
microscope work in hand is being carried on, for it disturbs neither
the microscope nor its adjustments.

This method has been tested with thirty- three object glasses,
ranging from a 3-in. to a yTrth of 1'4 IS". A., by fourteen different
makers, and with various eyepieces, on three different microscopes
with different tube lengths, and it has been found correct.

My best thanks are due to Mr. Grundy for his kind assistance and
notes. Further experience has shown that in determining the
" constant " it is better to measure the magnifying power by

242 E. M. NELSON ON A NEW METHOD OF MEASURING THE

direct projection on to a scale, without the intervention of any
camera lucida or drawing instrument ; the position of the
Ramsden's disc, from which the 10-in. projection distance is
measured, is easily found by means of a piece of ground glass.
An excellent scale for the measurement of low powers is a
Lufkin 3-in., No. 2111, price Is.

[Practical members ma} 7 , by this time, be ready to ask, " What
is the practical use of this system ? ' As a general answer it
might be said that it shows how the materials for an important
microscopical measuring tool can be easily determined.

But another practical reason for my taking interest in our
veteran member's paper is the hope that it will stimulate some
of us to take an increased interest in microscopical measurements.

I hardly need to impress on members the value of actually
measuring objects, beyond offering a reminder, that measurements
are the fundamental basis of microscopical science, and of every
branch of science. Some would, perhaps, claim to put mathe-
matics in this honourable position, but mathematics would be in
a most sorry plight without measurements in various forms.

Mr. Nelson, in a letter, says : " The combined magnifying
power is wanted for drawings. Beale's method of exhibiting a
drawing of the stage micrometer with the picture is quite the
best, but it is adopted by only a few authors." And he mentions
an instance of great trouble being caused by some drawings in
books on microscopical subjects having the magnifications wrongly
stated in the legend.

It will have been noticed that Mr. Nelson has, hitherto, con-
fined the use of the "eyepiece constant," for one eyepiece, to one
definite tube length for one constant ; but used it for getting
the total magnification with varying powers of objectives.

Tests have, however, shown that the total magnification can be
determined, by his method, for different tube lengths just in the
same way as for different powers of objectives. Mr. Nelson
himself says that " increase of tube length increases the power
and, of course, diminishes the field, and is just the same as
putting a higher-power objective on the nosepiece ; the constant
of the eyepiece remains the same." In support of this statement,
I give below r a few of the results of experiments made by Mr.
Nelson not many days ago.

MAGNIFYING POWER OF A MICROSCOPE.

243

Tests with Powell & Lealand's Low-angled ^in. Objective.

Eyepiece.

Tube length.

Diameter of field.

Magnifying power.

Eyepiece constant.

No. 1

12 in.
5 .,

0-036
0-0675

103
56

3-708
3-7N

No. 2

12 in.

6

0-031
0-0615

135

7(>

4-185
4-305

No. 4

12 in.

6

0-0267
0-052

267
135

7-129
7-02

Other Tests with ^-in. Objective.

Eyepiece constants.

Eyepiece.

Tube length, 8*75 in.

Tube length, 6 - 7 in.

A(E)
Z 12 C

W 1
2

K3

613

5-2
3-69
413
5-64

6-04

51

3-54

4-10

5-6

Tube length, 14*6 in.

Tube length, 5 -3 in.

K3

5-62

5-64

Magnifications . . 250

94

Notice how nearly alike the eyepiece constant is for each pair
of tests when different tube lengths are used, but the same eye-
piece and objective. The last pair are practically the same,
although the tube lengths vary to an extraordinary extent.
Mr. Nelson says that "they are all done with extreme accuracy
by projection. In every case the Ramsden's disc was found and
the screen placed ten inches from it." The magnifications were
250 and 94 diameters.

There is another easy way in which the information given by
the " eyepiece constant " may be used for determining the total
magnification for any tube length. Suppose, for example, the
eyepiece constant has been obtained with a given objective, eye-
piece, and tube length, a record being made ; then it is only
necessary to work a very simple proportion sum to determine at
any time the total approximate magnification with any tube

244 E. M. NELSON ON MAGNIFYING POWER OF A MICROSCOPE

length. All other conditions being the same, the total mag-
nification will be proportional to the tube lengths used.

Take the extraordinary difference of tube length shown by the
figures given below :

Tube length. Magnification.

14-6 in. 250

5-3 in. 94

Then

Magnifica-
Magnification with long tube x short tube length 250 x 5-3 tion for

short tube
length.

Magnifica-
tion for

Snort tube length. 5 # 3 ' long tube

length.

It is also worth mentioning that the diameter of the field may
be measured in millimetres, instead of inches, if millimetres are
used when determining the value of the eyepiece constant. And
members will probably find this a great convenience.

J. Grundy.]

Long tube length

14-6

And

Magnification with short tube x long tube length

94 x 14-6

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII. , No. 73. November 1913.

245

PROCEEDINGS

OF THE

QUEKETT MICROSCOPICAL CLUB.

At the meeting of the Club held on March 25th, 1913, the
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the
minutes of the meeting held on February 25th were read and
confirmed.

Messrs. J. T. Cook, David Henry Shuckard and W. E.
Ford-Fone were balloted for and duly elected members of the
Club.

The Hon. Secretary announced that Mr. G. T. Harris, of
Sidmouth, a former member of the Club, had made a very
handsome donation in the form of a type collection of Hydrozoa,
numbering 72 preparations. These had been collected on the
south-west and west coasts of England, and should prove
very useful to any member making a systematic study of the
group, especially as the slides are accompanied by a resume as
a help in diagnosing the more difficult species. Mr. Harris
also sent a paper which will be read at the next meeting, on
"The Collection and Preservation of the Hydrozoa."

A vote of thanks to Mr. Harris for his valuable donation
was proposed by the President, and carried by acclamation.

Mr. A. A. C. Eliot Merlin, F.R M.S., sent for exhibition five
photomicrographs, taken at x 320, of diatoms from a slide
prepared by the late C. Haughton Gill (see Journal R.M.S.,
1890, p. 435). They were of Epithemia turgida, Stauroneis
phoenice7ite?'07i, Pinnularia major, under surface showing per-
forations on ribbing partly filled with the mercurous sulphide,
and two others.

A paper by Messrs. Heron-Allen and Earland, "On some
Foraminifera from the Southern Area of the North Sea, dredged
by the Fisheries cruiser ' Huxley ,'" was read by Mr. Earland.
Mr. Earland said that after the reading of the paper by Mr.
Heron-Allen and himself, " On the Occurrence of Saccammina

246 PROCEEDINGS OF THE

sphaerica and Psammosphaeria fitsca," before the " Challenger "
society in October of last year, Mr. J. 0. Borley, of the Fisheries
Department of the Board of Agriculture, suggested that it would
be interesting if they continued their investigations in the
southern area of the North Sea with a view to determining the
distribution of the two species in that area. This, after some
hesitation, they agreed to do ; but with little expectation that
any observations of interest would result, as Mr. Borley had
already confirmed, from his personal experience, the generally
held opinion that Foraminifera of all kinds were of extremely
rare occurrence in these waters. The shallowness of the sea,
and consequent disturbance due to wave and tidal action, were
considered to be factors limiting the possibilities of Khizopodal
distribution. Material was examined from six stations repre-
senting two widely separated areas of the North Sea, three
stations being far to the north-east of the Dogger Bank near the
Great Fisher Bank, while the other three stations were in the
belt of deep water which lies to the west of the Dogger, close in
to the Northumberland coast. The depths ranged between 31
and 45 fathoms.

A number of photomicrographs were projected upon the screen,
and briefly described by Mr. Earland. Nubecidaria lucifuga
(Def ranee), a southern form, has an extended range as far as
the English Channel. It is common at Bognor and Selsey, and
a few specimens had been found near the Orkneys and in Moray
Firth. Miliolina seminulum (Linne) occurs at every station in
both areas. It is the dominant miliolid of the North Sea, and
is of world-wide distribution. Of the two species especially
searched for Psammosphaera fusca (Schulze) was found to occur
at all stations except one in the inshore area. Saccammina
sphaerica (Sars) does not occur in any of the outer, or Great
Fisher Bank, collections, but does occur at two inshore stations.
The specimens found were extremely small. The dominant
arenaceous form was Eeophax scorpiurus (Montfort). The
dominant Textularian was Verneuilina polystropha. It occurred
in great numbers and variety at every station. The genus
Lagena is abundantly represented in the inshore station dredg-
ings, twenty-eight species being recorded, while at the outer
stations only eight species were found. Truncatidina lobatula
(W. and J.), Nonionina depressula (W. and J.), and Polystomella

QUEKETT MICROSCOPICAL CLUB. 247

striato-punctata (F. and M.) occur abundantly everywhere, and
form the bulk of all the cleaned material.

The President, in proposing a vote of thanks for the paper,
said he much admired the photographs shown, which were the
best of the kind he had seen. He would like to ask Mr. Ear-
land, with regard to the criteria of specific characters, How
could one tell one species from another, seeing that there is so
much variation within the same species ?

The vote of thanks was carried unanimously.

In replying, Mr. Earland said he had to thank Mr. A. E.
Smith for making the negatives, and Mr. Lovegrove for the
lantern slides. Regarding specific differences, probably Prof.
Dendy would have no difficulty in identifying sponges which he
(Mr. Earland) would not be able to tell one from another.
There are constant points always present which make it more
or less easy to diagnose within certain limits. As regards specific
features in Foraminifera, there are none such as we find between,
say, a cat and a dog. Probably generic differences in Fora-
minifera are about equal to specific differences in higher forms.

Mr. D. Bryce gave a resume of a paper he had contributed
on " Five New Species of Bdelloid Rotifers." Four of the new
species belong to that important section of the Philodiniclae in
which the food is formed into pellets after passing through the
mastax, and are assigned to the genus Habrotrocha. The new
species are IT. munda, H. torquata, U. spicida, and H. ligula.
The fifth species, Callidina Bilfingeri, belongs to the more
numerous section of the same family in which the food is not
at any time agglutinated into pellets, and being oviparous, and
possessed of three toes, is a member of the genus Callidina, as
now restricted.

The President said they were all much indebted to Mr. Bryce
for bringing these interesting details before them.

A vote of thanks to Mr. Brvce for his communication was
carried unanimously.

At the meeting of the Club held on April 22nd, 1913, the
Vice-President, E. J. Spitta, L.R.C.P., M.R.C.S., in the chair,
the minutes of the meeting held on March 25th were read and
confirmed.

248 PROCEEDINGS OF THE

Messrs. F. J. Cheshire, Henry Edwards, and H. D. Rawson
were balloted for and duly elected members of the Club.

The List of Donations to the Club was read and the thanks of
the members voted to the donors.

Mr. C. D. Soar, F.R.M.S., read a note describing two new
species of water-mites. These were Arrhenurus Scourfeldi sp.
now and Acercus longitarsus sp. nov.. The first was taken by
Mr. Scourfield in Cornwall, in fresh water, in the autumn of
1912. It belongs to the sub-genus Megalurus, female unknown.
The new species of Acercus is named from the unusually long
tarsi found in the fourth pair of legs. Locality, South .Devon-
shire, female unknown. Mr. Soar also said that Mr. Williamson,
F.R.S.E., in working out the material on the genus Sperchon
had found two species new to Britain, and two that have only
been recorded for Ireland. These were Sperchon clupeifer Pier,
sub-genus Hispidosperchon, from Oban and Norfolk Broads.
Sperchon tenuabllis Koen, sub-genus Hispidosperchon, from
Oban. Recorded by Halbertin Clare Island Survey for Ireland.
Sperchon papillosus, Sig. Thor, sub-genus Squamosus, Oban,
recorded by Halbert for Ireland ; and Sperchon Thienemanni,
Koen, sub-genus Rugosa, from Derbyshire. Drawings of the
two new species were exhibited.

The Chairman said they were all deeply indebted to Mr. Soar
for bringing these new species of Hydrachnidae before them, and
they would be able to appreciate the value of the paper more
when in print. The drawings in illustration of the species
described were very tine indeed.

The thanks of the meeting were unanimously voted to Mr. Soar
for his paper.

In the absence of the author, the Hon. Treasurer, Mr. F. J.
Perks, read a paper on " The Collection and Preservation of the
Hydroida," by Mr. G. T. Harris, of Sidmouth, a former member
of the Club. The author said that the Hydroida are too well
known as affording both beautiful and interesting objects to need
any eulogy at his hands. Bearing in mind that this paper is
written more for the help of the novice than as a communication
offering original matter, the writer wished to safeguard himself
from any charge of carelessness by warning the uninitiated that
collecting, say, rotifers and collecting hydroids are two totally and
very dissimilar things.

QUEKETT MICROSCOPICAL CLUB. 249

A hearty vote of thanks was given to Mr. Harris for his
interesting paper, which was well illustrated by about twenty
preparations from those which he had presented to the Club at
the March meeting. The preparations were arranged, mostly
with dark-ground illumination, under microscopes kindly lent by
Messrs. H. F. Angus & Co.

The Chairman, in moving a vote of thanks to Messrs. Angus,
which was carried bv acclamation, said that in London members
took for granted that there was never any difficulty in getting
their optician friends to lend the Club any reasonable number of
microscopes ; but, as he had found by recent experience, outside
of London such a thing was practically an impossibility ; even in a
large town the number of microscopes available was very small.
By being reminded of this he hoped they would more fully appre-
ciate their good fortune.

At the meeting of the Club held on May 27th, 1913, the
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the
minutes of the meeting held on May 22nd were read and con-
firmed.

Messrs. Stanley Hall and Reginald Hook were balloted for and
duly elected members of the Club.

The list of donations to the Club was read and the thanks of
the members were voted to the donors.

The President said that for many years past a number of
pamphlets, etc., had been received by the Club, which, not being
considered of sufficient value to bind, had bden allowed to
accumulate and were stored in a room downstairs. These had
long been a kind of white elephant to the Committee, who had at
length decided to deal with them, and had appointed a sub-com-
mittee for this purpose. These gentlemen had gone through
them and had come to the conclusion that a large mass of this
material must be disposed of, and the question arose as to how
this was to be done, and it had been resolved to offer the bulk to
some dealer in second-hand books, but first of all to offer them to
the members of the Club. For this purpose, lists would be pre-
pared and laid upon the table at the next Gossip meeting and
again at the next Ordinary meeting, for members to inspect and
to make offers for any which they might care to possess. The

Journ. Q. M. C Series II. No. 73. 17

260 PROCEEDINGS OF THE

Librarian was empowered to receive such offers for them and to
accept those which he deemed satisfactory. It was not possible
to bring them up for inspection, as there was about a ton and
a half of them.

A visitor, Mr. J. Watson, exhibited multiple images formed by
the cornea of the eye of a hive bee mounted dry.

Mr. J. Watson said the slide was that of the eye of a honey
bee prepared so as to show the portrait of the bee-keeper in every
facet just as the bee would see it. He had been told it could be
done with the eye of a beetle, but that the hairs on the eye of the
bee made it a difficult matter to accomplish; but by mounting the
object in the way he described, so that the hairs were free from
pressure on the under side of the slide, he had succeeded in
obtaining the desired result, and he had obtained a good photo-
graph of it with half an hour's exposure.

The President said that at a Society such as theirs it w r as
needless to explain that this was not the view which the bee got,
as no doubt in some way it saw a single image, but he just men-
tioned this to prevent any mistake, as he thought he heard it
stated that this was how the bee saw the bee-master. Multiple
images such as were shown could be got in a variety of ways, and
he remembered that exactly the same thing was done at one of
the Royal Society's soirees with the epidermic cells of a plant.
They were, however, much obliged to Mr. Watson for bringing
and explaining his exhibit.

Mr. E. Inwards had found that a small knob fitted near the
hinge -joint of the stop-carrier of substage condensers was more
convenient in working than having to feel on the right for the
usual long projecting end, which is very often in close proximity
to the iris-handle.

Mr. T. A. O'Donohoe read a paper illustrated by a number of
lantern photographs, at various degrees of magnification, of the
" Minute Structure of Coscinodiscus asteromjrfialus and of the two
species of Plenrosigma, P. angulatium and P. balticum. Mr.
O'Donohoe then showed an interesting series of photographs, at
various magnifications, of P. balticum, some showing fine, hair-
like, bent fibrils breaking away from the valve. Others showed
the outer membrane breaking up into fibrils, and sometimes
isolated dots.

Mr. W. E. Brown said that the fibrils shown by Mr. O'Donohoe

QUEKETT MICROSCOPICAL CLUB. 251

had been known to him for a long time, but lie had never
regarded them as structure, but rather as salt which had
crystallised out after mounting. All these fibrils consisted of
rows of dots connected by bars, and there always seemed to him
to be some difference between these and the general structure.

Mr. E. Pitt exhibited and described the Cambridge, Minot and
Spencer microtomes, and, after the adjournment of the meeting,
gave a demonstration of ribbon section-cutting.

A vote of thanks was accorded Mr. Pitt for his exhibition.

At the meeting of the Club held on June 24th, 1913, the
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the
minutes of the meeting held on May 27th were read and con-
firmed.

Messrs. Frank Deed, C. Tierney, D. L. Newmarch, E. L.
Fen wick, and H. H. Dean were balloted for and duly elected
members of the Club.

The list of donations to the Club was read, and the thanks
of the members voted to the donors.

The Hon. Secretary read a note from Mr. E. M. Nelson
describing Koristka's new loup. The writer said that in 1885
he brought to the notice of the Club the then new Zeiss-Steinheil
loups, which had just arrived from Jena. These lenses have been
very popular, and have since been copied by every maker, both
here and on the Continent.

There is now a new form of loup with which the Club should be
acquainted; it is the achromatic doublet of Koristka. The following
are the measured particulars (not taken from a catalogue) :

Doublet, power 10, field 1| cm., working distance 2 cm.

Top lens alone, ,, 5|, ,, 2 ,, 4

Bottom lens alone, ,, 3|, 4 ,, ,, 5

The defining pow r er of this loup is excellent, and prolonged
work with it seems easier than with a Steinheil ; somehow or
other work with a Steinheil is tiring to the eye. The price of
this fine lens, in a wooden box, is only 12s., but although the
price is so low, the quality of workmanship is particularly high.
Among cheap loups we so often find that the lenses are im-
perfectly polished, the threads of the screws badly cut, so that
they do not engage readily, and the quality of materials used

252 PROCEEDINGS OF THE

inferior. But this new loup exhibits none of these defects, and
Koristka is to be congratulated on having brought out at a low-
figure a loup which compares favourably in the quality of its
finish with the most expensive grades of work in this line. This
high standard of workmanship extends also to Koristka's
objectives, eye-pieces and other apparatus.

Mr. A. A. C. Eliot Merlin, F.R.M.S., sent a note on " Secondary

Hairs on Foot of a Ceylon Spider." The main hairs on the foot

of a very large species of Ceylon spider, the name of which is

unknown, have proved to be densely covered with small short

spines or hairs so transparent as to be observable with difficulty

even by means of an oil-immersion objective. The specimen

examined was obtained and mounted in balsam by the late

Staniforth Green, who was for many years resident at Colombo.

When the main hairs are viewed with a dry lens, of moderately

large aperture they plainly exhibit a regular clotted structure,

this being composed of the ring root sockets of the secondary

spines, which are themselves so transparent in the balsam mount

as to require great aperture to define properly. It is suggested,

however, that hairs from this, or similar, large species of spider

might be mounted in glycerine jelly and might then exhibit the

spines more easily. The preparation in which the spines have

been noted happens to be, like most entomological mounts

intended for examination under low or medium powers, provided

with a cover-glass of considerable thickness, while the foot itself

is large and by no means flat. Under these conditions an

ordinary oil-immersion objective could not be employed, but

fortunately a Powell one-twelfth achromatic, of measured N.A.

1*27, obtained some fifteen years ago, possesses quite abnormal

working distance compared with recent productions of similar, or

slightly greater, aperture, and is to oil-immersion lenses what

the new one-sixth moderate aperture objectives of great working

distance are to dry systems. The lens in question has on several

occasions proved invaluable for the examination of minute

structure in ordinarily mounted entomological specimens. A

photomicrograph at x 60 accompanied the paper for identification

purpose, and was exhibited.

Mr. Nelson sent for exhibition a section of Green Trap, basic
igneous rock, a crystalline aggregation of serpentine. This, he
wrote, might easily be mistaken for a piece of fossil nummulite, or

QUEKETT MICROSCOPICAL CLUB. 253

wood. Xt is probable that the fossil known as Eozoon cauadense,
from the Laurentian serpentine, is of a similar nature.

Mr. H. Sidebottom contributed a valuable paper on "The
Lagenae of the South- West Pacific." Mr. A. Earland, F.R.M.S.,
in introducing this paper, said it was a very lengthy and valuable
one, and the Club would be proud to include it in the Journal.
It is Part 2 of a paper published in the April 1912 issue of
the Journal. By the kindness of Mr. H. F. Angus, who arranged
an exhibition frame for the drawings, he was able to exhibit
some of Mr. Sidebottom s beautiful drawings. The majority of
the stations from which the specimens dealt with were derived
(if not all) lie within the region of the South Pacific known to
oceanographers as the " Aldrich Deep." This area lies to the
east of New Zealand, between 15 and 47, and covers about
613,000 square miles. Three soundings exceeding 5,000
fathoms have been recorded in this area by Commander Balfour
in H.M.S. "Penguin" in 1895. The deepest sounding yet
made, however, is one in the "Challenger" Deep, near Guam,
in the Ladrone Islands. This is 5,269 fathoms, nearly six miles.
The Aldrich Deep has the second deepest record, 5,155 fathoms.
None of the material discussed in this paper comes from the
deepest parts of the area. The depths given by Mr. Sidebottom
range between 328 fathoms and 4,278 fathoms, but the majority
are under 2,000 fathoms. No details are given of the nature
of the material from which the specimens were derived, and
possibly the information was not in the author's possession, as
the majority, at any rate, of the specimens had been picked out
by Mr. Thornhill prior to his death, when the type slides passed
into the hands of Mr. Sidebottom for classification and description.
It may, however, be fairly surmised that, owing to the distance
of the area from any land, none of the samples would be terri-
genous deposits, but would be true oceanic deposits. Globigerina
and Pteropod oozes in the lesser depths, passing into pure
Globigerina ooze, and, beyond the 2,000-fathom line, into Red
Clay. The presence of a varied and rich fauna of Lagenaa in
the deep water of the South Pacific has been recorded by the
" Challenger" Some of the stations of that ship lie within the
same area as the " Penguin " material worked by Mr. Sidebottom,
but the " Challenger " material was either very poor in specimens
compared with the "Penguin" or it was very incompletely

254 PROCEEDINGS OF THE

worked out. The genus Lagena, while of world-wide distribution
and occurring at all depths, presents some rather curious
anomalies as regards its occurrence in any abundance. It
would probably be almost impossible to make a dredging or a
shore gathering in any part of the world without finding the
genus represented in the material. But, Mr. Earland said,
from practical experience, both of deep and shallow water
dredging and of shore collecting, he knew that in one sample
the genus may be extremely rare, while in another of similar
material taken a few miles away, under similar conditions of
depth, the genus may be abundant and varied. The reason for
such a difference is obscure, but is possibly based on the pro-
portion of mud in the deposit. Legena as a genus is a lover of
still and muddy bottoms. Globigerina oozes are, as a general
rule, singularly poor in Lagenae : hence the greater wonder at
the richness of the fauna in these " Penguin " oozes. Mr.
Sidebottorn states that the late Mr. Thornhill had picked out
over 12,000 specimens, and had commenced to arrange them on
a scheme which he had devised but did not live to carry out.
Personally, Mr. Earland said, he regretted that Mr. Sidebottom
had not found time or opportunity to use the unique material
which came into his possession at Mr. Thornhill's death, as a
centre around which to build up a complete monograph of this
beautiful genus. Perhaps he may yet find himself able to deal
with this task. But, in any case, it is a matter for congratula-
tion that Mr. Thornhill's work did not perish and disappear
unrecognised on his death, as so often happens when a worker
dies, but that his material has fallen into the hands of Mr.
Sidebottom, whose beautiful drawings will make it accessible to
all interested in the group.

One of the most noticeable features of this group is the very
large proportion of decorated forms. Many of the recognised
species are very hard to identify on account of the almost in-
finite variety and variation of the minute spines and markings
which characterise them. The object of such markings seems
to be quite beyond speculation. They are quite invisible to the
naked eye, and, unlike the markings of diatoms, do not appear
to have any physiological significance. Mr. Earland thought
the Club was to be congratulated on obtaining two such notable
papers for publication in its Journal,

QUEKETT MICROSCOPICAL CLUB. 255

The President said that he was afraid he was not able to
throw any light on the significance of the markings and char-
acters of the kind Mr. Earland had mentioned. He thought
they were quite inexplicable at present. It must be admitted
that a great number of specific characters are not due to adapta-
tions, and one may go further and ask how far the origin of
species is affected by natural selection. What proportion of
specific characters are adaptations at all ? How often can one
say that any character is really adaptive ? He would like the
opinion of some of the Club workers. Would Mr. Rousselet,
for instance, say that all the specific characters of rotifers were
adaptations ? He would not say an organism w r as not adapted
to its environment, but he would say that many organisms
exhibit a whole host of characters not due to environment.
They could not explain everything as due to natural selection.
Darwin laid great stress on " The Origin of Species by Means
of Natural Selection," and thought that specific characters came
first, and then natural selection came in and weeded out any
not suited to the environment.

Mr. C. F. Rousselet thought it was impossible to determine
what characters were really adaptive in the Rotifera.

Mr. D. Bryce said natural selection did not apply to his
Bdelloids, as they were all females. It was a real case of sur-
vival of the fittest. Occasionally a specific character must be
an absolute hindrance, and, in the case of long spines, must
sometimes be positively dangerous.

The President said it was very difficult to put oneself in the
position of, for instance, a sponge. But take the case, say, of a
small protuberance on a spicule, which spicule is quite sur-
rounded and embedded in the general protoplasmic mass of the
animal, and then assume another similar spicule which is without
such protuberance. It is not possible to conceive that either
the presence or absence of such a minute speck of silica could
be of any use to the individual, and yet such a difference is often
absolutely characteristic of a species. We have had instanced
this evening elaborate decoration and markings on Foraminifera.
These animals certainly cannot appreciate them visually, as they
have no organs of vision ; and, again, in life the markings would
be concealed under the usual gelatinous mass of exterior proto-
plasm. The markings are so minute that it is quite impossible

256 Proceedings of the

that the organisms could be cognisant of their existence in any
way. The markings are of such a nature as to be quite without
use to the organism, and we may take it that the possession of
one particular pattern is of just as much, or little, use to the
organism as the possession of any other pattern. Have we any
right to say that any one of the patterns is an adaptation ?

Mr. A. E. Hilton cited the case of the Mycetozoa, where the
specific nomenclature is based on minute markings on the capil-
litium. These markings are really the waste products of the
protoplasm which is purifying itself in spore-formation. It is
quite certain that the cause of the different markings must be
in the protoplasm itself. The protoplasm of different species
makes deposits in different shapes, and these must be largely
dependent on the condition of the air, as regards temperature
and moisture, at the times of spore-formation. The real seat
of the difference lies in the protoplasm itself.

Mr. W. It. Traviss exhibited and described a simple apparatus,
for use in pond-hunting, for collecting water from depths which
cannot be reached with the usual dipping-tube and stick. It
consisted of a light metal cylinder closed at one end. At the
other a light frame is fixed in a sort of handle-shape. This
frame serves as support to a stout metal rod, which is fastened
at the other end centrally to the bottom of the cylinder. On
the rod slides loosely, first, an easily fitting cap to the cylinder,
and, next, several lead discs. A string is attached to the bottom
of the cylinder actually to an eye formed by bending the end
of the central rod which is projecting outside. Another string
is attached to the opposite end of the rod. In use the weight
of the lead discs is so adjusted that they will take the cylinder
down to the bottom, upside down and full of air, the contrivance
being lowered by the string attached to the bottom, the other
string hanging slack. On reaching the bottom, or, if desired,
some particular depth which could be marked on the string, the
second string is gently pulled, bringing the mouth of the cylinder
away from the bottom, and permitting some of the contained
air to escape. Two or three tugs at the string will allow all the
air to rush out, and at the same time fill the cylinder with
bottom-water. It will now be right side up, and the lead weights
which carried it down will keep the loosely fitting lid in position
as the apparatus is drawn up by the top string. Practically no

QUEKETT MICROSCOPICAL CLUB. 257

exchange of water takes place. Mr. Traviss also exhibited a
very convenient and portable form of siphon-strainer.

Several members testified as to the efficiency of Mr. Traviss's
apparatus, which he used at the last excursion of the Club
(June 21st).

A paper " On a New Method of Measuring the Magnifying-
power of a Microscope," communicated by Mr. E. M. Nelson,
F.R.M.S., was read by Mr. J. Grundy.

After reading Mr. Nelson's paper, Mr, Grundy offered a few
remarks of his own.

Mr. Grundy exhibited a modification of the photomicrographic
camera projection method. A light cardboard tube of about
24 in. diameter and about 12 in. in length fits loosely over the
eye-piece ; the other end is supported by a clamp-stand. (The
microscope may be in any position; inclined is most convenient.)
At a distance of about 10 in. from the lower end a circle of fine
ground-glass is fitted. This is carried in a " draw-tube," per-
mitting correction for the position of the Ramsden disc for
various eye-pieces or for different tube-lengths. If a micrometer
is placed on the stage the projected image may be observed on
the ground-glass, and the divisions gauged with dividers, and
compared directly with an ordinary rule. Mr. Grundy also
exhibited microscopes fitted with Beale's neutral-tint camera-
lucida, Ashe's modification of Beale's form, and a Wollaston
model.

The President said they were much indebted to Mr. Nelson
for his paper, and to Mr. Grundy for reading it. He had himself
very often to make microscopical measurements, and though no
doubt the method described was very good in theory he did not
know how it would work out in practice as compared with the
very simple method which he was accustomed to adopt namely,
by drawing the object with a Beale's camera, and then in the
same way drawing the micrometer scale when placed on the
stage in place of the object. By applying these to one another
he could measure a thing in a very short time, and did not see
how he could possibly go wrong in so doing, although there might
be a slight distortion caused by the eye-piece.

A cordial vote of thanks was accorded to Mr. Nelson for his
useful paper, and to Mr. Grundy for the interesting way in
which he had brought the paper before the Club.

Journ. Q. M. G, Series II. No. 73. 18

258

OBITUARY NOTICE.

THE RIGHT HON. SIR FORD NORTH,
P.C., F.R.S., F.R.M.S.

Bom January \th, 1830; died October 12th, 1913.

We regret to record the death of Sir Ford North, one of our well-
known members. He died at his estate in Morayshire, in his eighty-
fourth year. He was the son of a solicitor, and became a barrister
practising in the Chancery Courts (1856). He was made a Q.C.
in 1877, and afterwards a judge, at first in the Queen's Bench
division (1881), and then in the Court of Chancery (1883), He
was a Fellow 7 of the Royal Society, and a well-known entomologist.
He was elected a member of the Q.M.C. in June 1894, and in the
same year F.R.M.S. ; hewasamember of our Committee in February
1899, and was one of our Vice-Presidents from February 1901.
His unassuming and cordial manner and the interest he displayed
in the objects exhibited by members produced a feeling of friend-
ship towards him in all those who had the pleasure of meeting
him, while his patience and experience in directing a meeting
when he occupied the chair, as was frequently the case, made him
a most valuable member of the Club, and one whose loss we all
greatly regret.

259

THE PRESIDENT'S ADDRESS.

ORGANISMS AND ORIGINS.

By Prof. Arthur Dendy, D.Sc., F.R.S.

(Delivered February 2ith, 1914.)

I have in my library a copy of a posthumous edition,
published in 1732, of a remarkable work by John Ray, entitled
" Three Physico-Theological Discourses, concerning I. The Primi-
tive Chaos, and Creation of the World. II. The General Deluge,
its Causes and Effects. III. The Dissolution of the World, and
Future Conflagration." The second of these discourses contains a
very long discussion on the origin of fossils, which begins as
follows : " Another supposed Effect of the Flood, was a bringing
up out of the Sea, and scattering all the Earth over, an innumer-
able Multitude of Shells and Shell-Fish ; there being of these
Shell-like Bodies, not only on lower Grounds and Hillocks, but
upon the highest Mountains, the Apennine and Alps themselves.
A supposed Effect, I say, because it is not yet agreed among the
Learned, whether these Bodies, formerly called petrified Shells, but
now-a-days passing by the Name of formed Stones, be original
Productions of Nature, formed in imitation of the Shells of
Fishes ; or the real Shells themselves, either remaining still
entire and uncorrupt, or petrified and turned into Stone, or, at
least, Stones cast in some Animal Mold. Both Parts have strong
Arguments and Patrons. I shall not balance Authorities, but
only consider and weigh Arguments."

In the end Ray pronounces in favour of the view that the
fossils are real shells and not mere sports of nature, but he adopts
a most singular hypothesis as to how they found their way into
their present situations. It is only fair to add that this hypothesis
did not originate with him, but was the offspring of the fertile
brain of his " learned and ingenious Friend, Mr. Edward Lhwyd."*

* 1 am indebted to rny friend, Mr. A. W. Sheppard, the Editor of this
Journal, for the information that Mr. Edward Lhwyd, M.A., F.R.S. , was
keeper of the Ashmolean Museum from 1690 to 1709, and published a
catalogue of fossils in 1699.

Journ. Q. M. C , Series II. No 74. 19

260 the president's address.

Mr. Lhwyd appears to have been much impressed by the
alleged fact that marine shells are sometimes generated in the
bodies of men and other animals, though at the present day it is
difficult enough to understand how such statements could ever
have gained credence. He observes : " For to me it appears a far
less Wonder, that Shells and other Marine Bodies should be pro-
duc'd in the Bowels of the Earth, than their Production in the
Bodies of Men or Animals at Land, And that they have been
so found, is sufficiently attested, both by Ancient and Modern
Authors, of a Credit and Character beyond all Exception."
Obviously the universal deluge could hardly be held responsible
for the occurrence of marine shells in human bodies, and there-
fore why hold it responsible for the occurrence of similar things
in the bowels of the earth %

The ingenious Mr. Lhwyd proceeds as follows : " I therefore
humbly offer to your Consideration, some Conjectures I have of
late Years entertain'd concerning the Causes, Origine, and Use
of these surprising Phenomena. I have, in short, imagin'd they
might be partly owing to Fish Spawn received into the Chinks
and other Meatus' s of the Earth in the Water of the Deluge, and
so be deriv'd (as the Water could make way) amongst the
Shelves or Layers of Stone, Earth, &c. and have farther thought
it worth our Enquiry, whether the Exhalations which are raised
out of the Sea, and falling down in Rains, Fogs, &c. do water
the Earth to the Depth here required, may not from the
Seminium, or Spawn of Marine Animals, be so far impregnated
with, as to the naked E}^e invisible, animalcida, (and also witli
separate or distinct Parts of them) as to produce these Marine
Bodies, which have so much excited our Admiration, and indeed
baffled our Reasoning, throughout the Globe of the Earth. I
imagin'd farther, that the like Origine might be ascribe! to the
Mineral Leaves and Branches, seeing we find that they are for
the most part the Leaves of Ferns, and other Capillaries ; and of
Mosses and such like Plants, as are called less perfect ; whose
Seeds may be easily allow'd to be wash'd down by the Rain into
the Depth here required."

You will note that the Deluge has not completely disappeared
from the hypothesis after all, but we may gather from what follows
that it has crept in rather by force of habit, and that the author
really relies principally upon the clouds and rain for conveying

THE PRESIDENT'S ADDRESS. 261

the " Seininium " into the crevices of the rocks where it is
supposed to develop. Indeed, he accounts in this manner for the
fact that so many of the fossil shells found in Great Britain
belong to species not found in the adjacent seas. The " Seininium"
has been brought from distant regions in the rain-clouds.

In order to make his argument more convincing, Mr. Lhwyd,
who is quite aware of some of its weakest paints, adopts the
well-known method of answering possible critics in advance.
" First" he says, "It will be questioned whether the supposed
Seminium can penetrate the Pores of Stones." To this he replies
" That it's manifest from Experience, upon which all solid
Philosophy must be grounded, that the Spawn of Animals may
insinuate itself into the Mass of Stone. And this plainly appears
from Live Toads, found sometimes in the middle of Stones at
Land, and those Shell-fish called Pholacles at Sea." In other
words, facts are facts, and there is no getting away from
them. " Secondly, 'It will scarce seem credible' that such Bodies,
having no life, should grow, especia'ly when confined in so
seemingly unnatural a Place as the Earth, &c." The answer
to this is again supplied by the voice of authority, supplemented
by an original observation on the part of the author which in-
dicates clearly enough the amount of reliance that is to be placed
upon his conclusions. " That's not so great a Wonder," he says,
" as that Shells should be sometimes generated, and even grow,
tho' they contain no Animals, within humane Bodies ; and within
the Mass of those thick Shells of our large Tenby Oysters,
which I formerly mentioned to you, as first shown me by Mr.
William Cole of Bristol, and have since observ'd myself. For
we must grant, that the Earth, even in any Part of the Inland
Country, is much fitter for their Reception and Augmentation
than humane Bodies ; especially, if we reflect, that when the
Spat or Seminium here suppos'd meets with saline Moisture
in the earth, living Animals are sometimes produced, as is before
attested." And so on to ninthly and lastly.

Evidently, in the year 1698, when this was written, the
problem of how the apple got into the dumpling had not
yet been solved by the philosophers. It is a little surprising,
however, that such views should have been accepted by so
experienced an observer as John Bay, who has been called
the Father of modern zoological science. Nevertheless, he

262 the president's address.

quotes them at length, and adds : " For my part (if my Opinion
be considerable) I think that my learned Friend hath sufficiently
proved that these Fossil-shells were not brought in by the
universal Deluge. He hath made it also highly probable, that
they might be originally formed in the Places where they are
now found by a spermatick Principle, in like manner as he
supposes. Why do I say probable ? It is necessary that at least
those, which are found in the Viscera and Glands of Animals, be
thus formed ; and if these, why not those found in the Earth ?
I shall say no more, but that those who are not satisfied with
his Proofs, I wish they would but answer them." Thus even
Kay, who was turned out of his Fellowship at Cambridge because
he refused to make a declaration with regard to the Solemn
League and Covenant demanded by the authorities, allowed
himself to be completely enslaved by his own credulity with
regard to unverified and, indeed, absurd statements as to the
occurrence of marine shells in the bodies of land animals !

I suppose that Mr. Lhwyd's quaint hypothesis was almost the
last of the many curious attempts that were made to explain
the existence of fossils before our modern views on the subject
came to be generally accepted. It affords an interesting illustra-
tion of the power of uncriticised authority to lead people astray.
Unfortunately, however, we cannot do without authority in science.
No man has either time or opportunity to prove all things for
himself. Progress is rendered possible only by the accumulation
of the labours of many workers, each relying upon his fellows.
The only safeguard against error is the free exercise of our
critical faculty and the due restraint of our natural credulity
the original sin of the scientific man.

Let us turn now to another hypothesis. In 1875 Prof. Huxley,
in one of his extraordinarily stimulating essays,* discussed the
relation which exists between the composition of the earth's
crust and the organisms by which it has been populated. He
points out that the great Swedish naturalist Linmeus, who was
born in 1707, only two years after the death of Kay, had already
enunciated the dictum that "fossils are not the children, but the
parents of the rocks " in other words, that rocks originate from

* "On Some of the Results of the Expedition cf H.M.S. Challenger"

1875]. Collected Essays, vol. viii.

THE PRESIDENT'S ADDRESS. 263

animals and not animals from rocks (" sic lapides ab animalibus,
nee vice versa ").

.After discussing the character of the various deposits which
form the floor of the ocean, Prof. Huxley remarks : " If the
Challenger hypothesis, that the red clay is the residue left by
dissolved Foraminiferous skeletons, is correct, then all these
deposits alike would be directly, or indirectly, the product of
living organisms. But just as a siliceous deposit may be
metamorphosed into opal or quartzite, and chalk into marble,
so known metamorphic agencies may metamorphose clay into
schist, clay-slate, slate, gneiss, or even granite. And thus,
by the agency of the lowest and simplest of organisms, our
imaginary globe might be covered with strata, of all the chief
kinds of rock of which the known crust of the earth is composed,
of indefinite thickness and extent. . . .

" Accepting it provisionally, we arrive at the remarkable result
that all the chief known constituents of the crust of the earth
may have formed part of living bodies ; that they may be the
; ash' of protoplasm/'

The view that the red clay which forms the floor of the ocean
at very great depths, and extends over an area of about fifty
million square miles, is derived from the decay of the skeletons
of Foraminifera from which the lime has been dissolved out,
has not been substantiated by later investigations. According
to Sir John Murray, the greatest authority on the subject,
it has been formed chiefly by the disintegration of pumice and
other volcanic ejecta.

It thus appears that the " ash of protoplasm '' does not play
nearly such an important part in the formation of the earth's
crust as that suggested conditionally by Huxley.

My indefatigable friend, Mr. Kirkpatrick, however, has for
some time been raking in all sorts of ashes for evidence of their
origin, and has come to the conclusion that even in the most
unlikely situations traces of simple organisms may still be
found.* He has, I fear, as yet met with but little success in
convincing his scientific colleagues of the correctness of his
observations, but his results are certainly in close agreement
with the conclusions arrived at by Linnaeus and, provisionally,
by Huxley. If these conclusions were correct we should have
-* Vide The Niimmulosphere, by K. Kirkpatrick. London, 1913.

264 the president's address.

to conceive of the solid crust of the earth as the result of a
constant interchange of matter between the living and the
dead, accompanied by physical and chemical processes of endless
complexity. We might even think of it as a huge composite
organism, alive only at the surface, but built up on the waste
products of its own collective metabolism, like a world-embracing
coral reef. I fear, however, that such a conception would be
more picturesque than accurate.

Even if we accepted such a hypothesis we should, of course,
have to remember that such a state of affairs could only have
arisen through a slow and gradual process of evolution.
Whether this process occupied a hundred million or a thousand
million years would be a matter of comparatively small import-
ance. It would be enough for our present purposes to recognise
that it must have had a beginning at some extremely remote
period of geological time, when the crust of the earth could not
by any possibility have been composed of the detritus of living
things.

It is generally admitted that there are only two possibilities
with regard to the origin of terrestrial organisms. Either thev
must have been imported from some other planet in the form
of germs, or they must have developed on the earth's surface
from inorganic materials that formed part of the earth itself.
Either event could only have taken place after the earth had
cooled sufficiently to permit of the existence of those peculiarly
unstable colloidal compounds of which living bodies are composed.

The first hypothesis has, as you are aware, received the sup-
port of no less eminent a man of science than the late Lord Kelvin,
who believed it possible that the germs of living organisms
might have been brought to the earth by meteorites. The chief
objection to this view appears to be the difficulty of believing
that any organism could withstand the heat generated by the
friction of the meteorite with the earth's atmosphere.

A modification of the same hypothesis, sometimes known as
the Theory of Panspermia, is maintained by Svante Arrhenius
and others. According to this theory, numerous living germs of
extremely minute size occur scattered through space, derived
from various planets upon which life is supposed to exist,
though at present we have no proof whatever that life does
exist upon any pi met except the earth itself. The nature of

THE PRESIDENT'S ADDRESS. 265

these invisible germs is enigmatical in the highest degree. They
are supposed to be propelled through space by the pressure of
the radiant energy streaming from the sun and it has indeed
been demonstrated that very minute particles can be propelled in
this way by rays of light. It has been objected to this view
that no organisms could withstand the intense cold of inter-
planetary space, but we know that living organisms withstand
low temperatures much better than they withstand high ones,
and there appears to be no known minimum at which all life
is necessarily destroyed. A more serious objection is to be found
in what is known of the fatal effects of ultra-violet light rays
upon micro-organisms. At the surface of the earth such
organisms are to a large extent screened from the effects of
these rays by the earth's atmosphere, but this would not be the
case in interplanetary space.

Even if we were able to prove that living organisms first
reached the earth from some other planet, however, it would
not help us in the least to understand how they first originated.
Such a hypothesis can only serve to remove the scene of action
from the earth to some unknown sphere where the investigation
of the problem is altogether beyond our reach. We may just
as well assume at once that the first terrestrial organisms were
generated in situ upon the earth itself and endeavour to find out
how such generation may have occurred.

This brings us to our second alternative, which we may speak
of as the hypothesis of spontaneous generation, or, if we prefer
Huxley's term, abiogenesis. The discussion of this question has
unfortunately been greatly prejudiced by the hasty conclusions
of various observers who from time to time have announced that
they have actually witnessed the production of living organisms
from not-living matter, a claim which has been repeated at
intervals ever since people began to speculate on such subjects,
but which no one has yet succeeded in substantiating. I shall
refer presently to the latest efforts in this direction, but in the
meantime we must carefully bear in mind that the sudden
appearance of recognisable organisms where none previously
existed, and in situations to which no living things can have
gained access, is a very different thing from the gradual evolution
of living matter from inorganic substances by slow and imper-
ceptible steps, which are at first purely chemical and physical in

266 the president's address.

nature but gradually assume a character which distinguishes
them more or less from ordinary physical and chemical processes
and perhaps justifies us in speaking of them as vital.

That there should be perfect continuity between not-living and
living matter on the one hand, and between physico-chemical and
vital processes on the other, is clearly demanded by the doctrine
of evolution. Moreover we know that, at the present day,
inorganic matter is constantly being converted into living proto-
plasm, though only by the peculiar organising activities of
living bodies. All organisms assimilate materials derived from
their environment in order to build up their own bodies, and it
is largely this power of assimilation that distinguishes them from
bodies that are not alive. Daring life the organism conquers its
environment and appropriates such portions of it as it requires.
Death is the conquest of the organism by the environment,
accompanied by re-annexation on the part of the inorganic world
of all that the organism had appropriated during its lifetime.

The chemist has no difficulty in analysing the complex col-
loidal constituents of dead organisms into a descending series
of less and less complex substances, ending with the so-called
elements themselves. He has also, to a very great extent, accom-
plished the reverse process, and has already carried his constructive
operations as far as the synthesis of polypeptides, from which
point to the proteids themselves is but another step. He has no
right to assume, however, that when he has actually taken this
step and, further, mixed his proteids with the other substances
known to occur in living protoplasm, he will have produced
anything that is actually endowed with life. We may even say,
without much exaggeration, that the chemist, as such, has no
knowledge of protoplasm at all, for it is impossible to analyse
protoplasm while it is alive, and as soon as you kill it it ceases
to be protoplasm.

Even the simplest living things known to us behave in a
manner which cannot, at any rate in the present state of our
knowledge, be explained entirely in terms of chemistry and
physics. The living organism itself plays the part of the chemist
and the physicist, and we cannot explain the chemist or physicist
in terms of the chemical and physical operations which he per-
forms in his laboratory. Out of a multitude of possibilities the
living organism selects those materials and those modes of action

THE PRESIDENTS ADDRESS. 267

which are consonant with its requirements as a living organism,
and its power of meeting emergencies as they arise is the
measure of its power to survive. Moreover, it is able to profit
by experience and to learn how best to overcome the difficulties
presented by its environment. This being so, we are justified in
maintaining that even the simplest living thing is endowed with
a certain degree of intelligence, for intelligence is nothing but
the power of learning by experience how to perform purposive
acts.

We are not obliged, however, to suppose that the property
which distinguishes the living from the not-living intelligence,
vitality, or whatever we choose to term it came into existence
suddenly. It is more in accord w r ith our experience in other
directions to believe that it arose by imperceptible degrees,
pari passu with the evolution of organic from inorganic matter.
This, however, must not be taken to imply that there is no
essential difference between living and not-living bodies, either in
structure or behaviour. We might with equal justice say that,
because water is a compound of oxygen and hydrogen, there is
no essential difference between water and a mixture of these two
gases. We are told that to speak of the aquosity of water is
meaningless pedantry, and that to speak of the vitality of living
organisms is no less so. Of course, if such phrases are offered as
explanations of phenomena, they are entirely valueless ; but if
used merely as a kind of shorthand expression of the fact that
water and living organisms possess certain properties which dis-
tinguish them respectively from all other bodies, I see no more
harm in them than in any other technical descriptive terms. In
neither case can we supply a final explanation of the phenomena
to which we refer.

Every stage in the evolution of matter is accompanied by the
development of new properties or qualities which require the use
of new descriptive terms. As to the so-called forces which lie
behind these properties w T e know nothing. We can only classify
them, as a matter of convenience, according to the effects which
they produce. We speak of the force of chemical affinity, of the
force of gravity, of electro-magnetic force, and so on ; and if
we choose to express our conviction that none of the so-called
chemical and physical forces are adequate to explain all the
phenomena of life, there is no logical reason why we should not,

268 the president's address.

as a matter of mere convenience, speak of vital forces also.
Indeed, it appears to me more in accord with scientific method
to do this than to ignore the existence of such characteristic vital
phenomena as our own consciousness and intelligence or leave
them to be explained by supernaturalism.

After all, the quarrel between the vitalist and the mechanist is
chiefly over mere terminology. The vitalist knows perfectly well
that the organism may to a very large extent be looked upon as
a machine in which chemical and physical processes are utilised,
and the mechanist knows equally well that he cannot hope to
explain his own consciousness, and his own intelligent action,
in terms of chemistry and physics. If we recognise these two
facts it is a matter of comparatively small importance to decide
in what terms the unknown factors can best be described.

At any rate I see no reason why vitalists and mechanists should
not agree that living organisms first arose, either on our own
planet or elsewhere, by means of a complex process of physico-
chemical synthesis, in which the electron, the atom, the molecule,
the colloidal mult i- molecule and the simplest protoplasmic unit,
may be taken as representing the chief stages. This at any rate
is what we should expect from the study of those analytical and
synthetical processes with which the bio-chemist has familiarised
us, and from what we know of the process of evolution in
general.

What may be the nature of the simplest protoplasmic unit is a
question still under discussion. That it is not what we commonly
call a cell seems certain, for a cell has a complex structure which
must have been preceded by something very much simpler. The
differentiation into cytoplasm and nucleus, and, above all, the
extraordinarily complex phenomena of mitotic division, which are
observable in nearly all cases where a distinct nucleus is present,
can only have been attained as the result of a long process of
evolution. The existence of the Bacteria, in which, although
both cytoplasm and chromatin may be present, there is still no
properly defined nucleus, perhaps indicates one phylogenetic stage
through which the fully developed cell may have passed.

Possibly few biologists of the present day conceive of the most
primitive organisms as relatively large unnucleated masses of
structureless protoplasm, such as some of Haeckel's famous
Monera were supposed to be. " The entire body of these

THE PRESIDENT'S ADDRESS. 269

Monera," says Haeckel, "is throughout life nothing more than a
motile lump of slime without constant form, a small living bit of
an albuminoid carbon compound. We agree that this homogeneous
mass possesses a very complex minute molecular structure ; but
this is not anatomically or microscopically demonstrable. Simpler,
less perfect organisms are not thinkable." *

Recent researches, unfortunately, tend to throw considerable
doubt upon the existence of such Monera. It has been pointed
out that the failure to recognise a nucleus may have been due to
the imperfections of microscopical technique at the time when the
organisms in question were described. Even some of the Bacteria,
which Haeckel regarded as Monera and which are amongst the
smallest recognisable organisms, are now known, as we have just
seen, to exhibit well-marked differentiations in their protoplasm,
and many of the supposed " cytodes " or unnucleated cells, have
already been shown to possess a nucleus. With regard to others
the matter must be regarded as still sub judice.

Haeckel himself, it must be remembered, recognised the fact
that his Monera must be composed of ultra-microscopic molecules
or groups of molecules, which he spoke of as Plastidules or
Micellae, the latter term having been coined by Naegeli.

It is these ultra-microscopic and indeed purely hypothetical
particles of colloidal proteid that the modern biologist is inclined
to regard as representing the most primitive living organisms,
and Weismann has gone so far as to assign to them a definite
place in our scheme of classification, proposing for their recep-
tion the so-called family Biophoridae and identifying them with
the biophors or ultimate vital units of his well-known theory
of heredity.

It has further been pointed out that such minute particles of
living matter, far smaller than the most minute Bacteria, may be
arising all around us by so-called spontaneous generation at the
present day, without our being able to recognise the fact. It is
only when, in the course of evolution, they had become aggregated
in relatively large masses, that we could hope to see them even
with the highest powers of our microscopes. The justice of this
view might, however, fairly be questioned. When chemical mole-
cules arise in our laboratories by combination of atoms or of

* Translated from Haeckel's " Schopfungsgeschichte," Edition 9 (1898),
p. 165.

270 the president's address.

simpler molecules, they usually present themselves to us in
aggregates which are large enough to be at once recognisable,
and one would naturally suppose the same to be true of the
multi-molecules, biophors, or whatever we like to call them, of
which living matter consists. As a matter of fact, however, the
chief objection that I can see to the Monera theory is the
almost ultra-microscopical size of the simplest organisms actually
known to us. Indeed, it' we take into account the so-called filter-
passers, or Chlamydozoa, which are believed to be the germs of
certain diseases, but most of which we know only by inference,
we are justified in saying that the simplest known organisms are
actually ultra-microscopic.

It seems impossible to obtain any precise information as to the
size of the smallest particles that can be seen with the microscope.
Since this address was delivered, Dr. Spitta has been kind enough
to inform me that he has been able to see and photograph a
particle only 1/9 7,000th of an inch in diameter, and it will be
remembered that at a recent meeting of the Club Mr. Brown
claimed to have seen in the frustule of a diatom a pore the
diameter of which he estimated at 1/200, 000th of an inch. As the
filter-passing organisms are ultra-microscopic, they must be smaller
than this. Indeed, most of them have never yet been seen even
with the aid of the ultra -microscope, which, by a special method
of illumination, enables us to recognise the presence of particles
having a diameter of certainly not more than 1/2, 500,000th of an
inch and possibly a good deal less, though such particles cannot
be seen at all in the ordinary way by transmitted light.

It is only by inoculation experiments that we can prove the
existence of these ultra-microscopic parasites. Thus we are told
that if even so small a quantity as 0'005 of a cubic millimetre of
lymph from an animal suffering from foot and mouth disease
be inoculated into a healthy calf, the latter will in due course
contract the same disease, although the lymph, so far as micro-
scopic examination enables us to judge, is entirely free from
organisms.

Yellow fever, cattle plague, rabies and many other diseases are
believed to be caused by ultra -microscopic parasites. That such
diseases are due to living organisms and not to lifeless toxins is
indicated sufficiently clearly by the fact that a period of incu-
bation always follows infection, during which the poisonous matter

THE PRESIDENT'S ADDRESS. 271

increases in amount until there is enough to produce its deadly
effects, when the characteristic symptoms of disease manifest
themselves in the patient.

Buckmaster considers that most of the filterable parasites are
Bacteria, but as we know nothing of their structure it seems a
little premature to include them in any group which is based upon
morphological characters. They might be included in Weismann's
hypothetical Biophoridae, although, from the point of view of the
higher organisms, ; ' death -carriers" would certainly be a more
appropriate name for them than " life-carriers."

Inasmuch as all the known filter-passing organisms are
parasitic, it might be argued that their existence implies the
pre-existence of higher organisms, and that therefore they cannot
be regarded as themselves representing the most primitive living
things. Such an argument would, of course, be entirely
fallacious. It so happens that at the present time the only
means we have of recognising the most minute of these
organisms is by their effects upon other organisms. There may
be hosts of ultra-microscopic organisms living freely on the earth's
surface which have no recognisable effects upon the higher plants
and animals, and of whose existence we therefore remain in
complete ignorance. This would be quite in harmony with what
we know of the microscopically visible Bacteria. Some of these
live freely in the soil and are able to feed upon purely inorganic
substances, while others are far more familiar to us on account
of their influence, whether beneficial or disastrous, either upon
ourselves or upon other organisms in which we happen to be
interested.

Your late President, Prof. E. A. Minchin, who speaks with
great authority on such subjects, in his last address to the Club,
devoted some time to the consideration of the question whether
the extremely minute organisms which we have be?n discussing
consist of cytoplasm or chromatin, and pronounced in favour
of the latter alternative. For my own part I must confess that
I prefer the view that at this stage of evolution the distinction
between cytoplasm and chromatin has not yet arisen, a view
which, as Prof. Minchin pointed out, is in harmony Avith the
hypothesis of the evolution of living matter from inorganic sub-
stances on the earth rather than with that of its importation
from some other planet.

272 the president's address.

It follows inevitably from the above considerations that the
frequent failure of experimenters to demonstrate the occurrence
of spontaneous generation cannot be regarded as proof that it
never takes place even at the present day ; much less as proof
that it has never taken place in the past.

The classical experiments of Pasteur, Tyndall and other
observers of the nineteenth century, so far as they related to
spontaneous generation, seem to have been for the most part
confined to the problems involved in the occurrence of organisms
in organic infusions, such infusions being the media in which
most of the known micro-organisms naturally occur and from
which they derive their food-supplies. As a result of such
experiments it is generally believed to have been demonstrated
clearly enough that if adequate measures are taken in the first
place to sterilise the culture media by heat, and in the second
place to prevent the access of living germs after sterilisation
has been effected, such infusions may be kept for an indefinite
time without any organisms making their appearance in them,
and, consequently, without undergoing putrefaction. It is also,.
I believe, generally supposed, though with little justification,
that this conclusion applies to all culture media whatever,
whether organic or inorganic.

One observer, however, Dr. Charlton Bastian, whose earlier
experiments were contemporary with those of Pasteur and
Tyndall, and who has recently been again engaged in similar
investigations, has consistently maintained a different view.
His earlier experiments, like those of other observers, were con-
ducted with organic infusions, or with artificial nutrient solutions
such as ammonium tartrate or other salts of ammonia. The
positive conclusions arrived at by experiments with organic
culture media may be considered to have been completely nega-
tived by the general experience of bacteriologists during the
subsequent forty years.

With regard to the origin of living things from the inorganic
world, however, the negative results obtained by properly con-
ducted experiments with organic infusions are of comparatively
little value. If spontaneous generation takes place at all at
the present day it probably takes place as it must have done
at some time in the past, when no organic bodies existed to
supply food for the first living things. In other words, we

THE PRESIDENT'S ADDRESS. 273

should not expect to be able to observe spontaneous generation
in infusions of organic matter, but should conduct our experiments
with purely inorganic substances.

Dr. Bastian's a priori position is a very strong one. If
spontaneous generation took place once upon the earth's surface-
there is no known reason why it should not take place to-day,
while the actual existence of countless hosts of extremely
primitive organisms alongside the most highly finished products
of organic evolution certainly seems to support the view that such
primitive forms are constantly arising from inorganic constitu-
ents and emerging from the obscurity of their birth only when
they have reached a stage of evolution at which they are capable
of appealing directly or indirectly to the human senses.

Dr. Bastian employed for some of his recent experiments* a
very dilute solution of sodium silicate, to which was added either
a minute quantity of pernitrate of iron, or a small quantity of
phosphoric acid and ammonium phosphate. He joints out r
however, that the sodium silicate is a variable commercial product
and attributes to this fact certain otherwise unaccountable
variations in the results obtained. The experiments were there-
fore repeated with pure colloidal silica in place of the sodium
silicate, and positive results were again secured.

The method of procedure is as follows. The solution to be
experimented upon is hermetically sealed up in a glass tube
and heated to about 130 C. for ten minutes or more. After the
lapse of a few weeks, or in some cases months, during which time
the sealed tubes have been exposed to ordinary atmospheric
conditions, they are found to contain living organisms, Torulae y
Bacteria and even moulds being present in varying quantities.
Dr. Bastian claims that these organisms have arisen in the
tubes by spontaneous generation, or, as he terms it, Archebiosis.
He supposes that the living matter probably originated in
the first place in the form of ultra-microscopic particles, but
maintains that in the course of a few weeks or months these
particles developed into the organisms finally found.

To a certain extent these results are, as I have already pointed
out, in accord with purely a ])riori expectations, but in other
respects they appear improbable to the last degree. Most of the

* For a full account of these experiments the reader is referred to
Dr. Bastian's recent book on The Origin of Life. 2nd Edition, 1913.

274 the president's address.

organisms produced are of well-known types, and one of the
moulds formed appears to be a Peniciliium producing spores
in the ordinary way. I must confess that I myself find it
impossible to believe without much stronger evidence that such
comparatively highly organised beings can have been evolved so
rapidly from ultra- microscopic germs. We are accustomed to
think of evolution as a very slow and gradual process, and we
know that Bacteria, Torulae and moulds may be cultivated for
an indefinite period without undergoing any recognisable change ;
indeed many industries, such as brewing, wine-making and
cheese-making, depend for their very existence upon this
fact. May we suppose that all these organisms have reached
the limits of their evolution? If so we have the answer to
the question, why have they remained stationary while other
organisms have developed into the higher forms of plants and
animals ? If, however, we are asked to believe that the Bacteria
and Torulae are stages in the evolution of the moulds, why does
not this transformation manifest itself in our everyday experience ?
Dr. Bastian himself, it should be observed, is a convinced
upholder of the doctrine of heterogenesis, or the sudden appear-
ance of one kind of organism as the offspring of another, but
it may be doubted whether any other living biologist holds similar
views.

Again, are we to believe that such organisms arise in nature
under many different conditions and from many different
mixtures of chemical compounds, or are we to believe that
Dr. Bastian has accidentally, and almost at the first attempt,
hit upon just the right materials and the right conditions for the
production of well-known living things 1 His own observations,
if correct, show that the experimental solutions may be varied
within wide limits, but this is hardly what we should expect if
the origin of living things is to be regarded as a mere stage in a
series of chemical and physical processes. Another criticism
of these results may be based upon the fact that the materials
employed do not (unless accidentally) contain all the necessary
ingredients of protoplasm. Carbon is apparently entirely
wanting, and we must either suppose that it is accidentally
present in minute but sufficient quantities as an impurity, or
else that it can, as Dr. Bastian actually suggests, be replaced,
to a greater or less extent, by silica in his organisms. It has

THE PRESIDENT'S ADDRESS. 275

been suggested that the colloidal character of the silica employed
is especially favourable to the evolution of living matter, but
unless the organisms are largely composed of silica, which is
highly improbable, it is difficult to see exactly what the colloidal
silica has got to do with their origin, unless, indeed, it may be
supposed to act as a catalytic agent.

Altogether I think we may fairly say that the acceptance
of Dr. Bastian's results would involve us in so many difficulties
that it is preferable at present to believe that there has been
some error in his mode of procedure, some unsuspected loophole
through which contamination of his preparations has taken
place.*

The whole problem looks surprisingly like a modern version
of the old story with which we started. The question " What
was the origin of the fossils in the rocks ? " is replaced by the
question " What was the origin of the organisms in the glass
tubes 1 ' : We have seen how, in the former case, certain
statements, made apparently in perfectly good faith, led to
entirely wrong and absurd conclusions. We are all agreed
now as to how the fossils got into the rocks, but I am not aware
that anyone has ever succeeded in explaining the mystery of
how the marine shells got into the human body, or even how
the toads got into the stones in which they were alleged to have
been found. .No one, however, whose opinion is worth con-
sidering, believes that they were generated there. All are
agreed that there must have been something wrong with the
original statements, and there we must be content to leave
it. It is doubtless premature to say that Dr. Bastian's
organisms are merely toads in stones, but I do not see much
to choose between the difficulties of explanation in the two
cases. The decision must be left to the future, and in the mean-
time we may console ourselves with the reflection that science

* Since this address was written Dr. Bastian has published a lengthy
communication in Nature (January 22nd, 1914) in which he tells us that his
results have been confirmed by four other observers, two in America and
two in France. The American observers say, however, " We have no sug-
gestion to make other than your interpretation, and, indeed, we desire to
be entirely non-committal as yet." Prof. Hewlett, the well-known bac-
teriologist, writing at the same time, states that, although he has made
similar experiments, he has not yet been able to confirm Dr. Bastian's
results.

Journ. Q. M. C, Series II. No. 74. 20

276 the president's address.

cannot be infallible, but can progress only by a process of natural
selection, in the course of which one hypothesis replaces another
in the struggle for existence. The buckets in which we draw up
truth from the bottom of the well are very small and very leaky,
and a good deal that is not truth finds its way into them before
they reach the surface. Fortunately the impurities, even if they
cannot be eliminated at once, sooner or later sink to the bottom
and leave the water clear.

Journ. Quekctt Microscopical Club, Scr. 2, Vol. XII., No. 74, April 1914.

277

A CHANGER FOR USE WITH SUB-STAGE

CONDENSERS.

By S. C. Akehurst, F.R.M.S.
Bead October 2Mb, 1913.

Figs. 1 and 2.

Petrological microscopes have been fitted in various ways to
arrange for a quick change of sub-stage condenser, and I have
frequently felt the need of a similar method applied to a

Fig 1.

biological microscope. I found the revolving nose-piece to carry
three condensers did not work satisfactorily, therefore adapted
the principle employed in the sliding objective changer to the
sub-stage fitting, and found this enabled me to get an easy and
rapid change of condensers.

The scheme consists of a metal slide 2| x If, with bevelled
edges, on which the condenser is mounted, and, when necessary,
a throw-out arm for stops, and an iris diaphragm. Two D-shaped

278 S. C. AKEHURST ON A CHANGER FOR SUB-STAGE CONDENSERS.

metal plates, the flat sides of which are set 1| inch apart, form
a groove for the slide to work in. These plates are screwed to a
metal collar, the diameter of which is such as to allow the slide-
condenser changer to be fitted to any microscope that has a sub-
stage made to the R.M.S. gauge. Fig. 1 shows a plan of the
slide changer in position, while fig. 2 gives a sectional elevation
along the line A B, fig. 1. When three, or more, condensers are
used it is desirable to have each mounted on a separate slide ;
but when only two condensers are used, one slide may be
sufficient, as the optical parts can be made interchangeable.

Fig. 2.

When the slide with condenser has been pushed home, a screw,
working through one of the plates, holds this firmly in position.

This changer does away with the necessity of a throw-out
sub- stage, and any variation of centrality in the condenser can
be adjusted by the centring screws in the regular way.

To rack down the sub-stage fitting, withdraw and insert a new
slide, are all the movements that are required to obtain a change
of condenser, and this can be effected as readily as a change of
objective on a revolving nose-piece.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914.

279

A TRAP FOR FREE-SWIMMING ORGANISMS.

By S. C. Akehurst, F.R.M.S.

{Bead October 2H(h, 1913.)

Fig. 3.

Simply stated this is an arrangement which cuts off the retreat
of the creatures after they have been attracted into a small
receptacle by light.

The first trap I used was made of glass in two pieces. The
top is funnel-shaped, and holds about 5 ounces of water. This
is attached to a horizontally-placed cylinder, 1 inch in diameter,
and 1| inch long the whole being mounted on a stem and foot.

Into the cylinder is fitted a glass spigot, which has been ground
in to avoid water passing. There is a hole at the bottom of the
funnel flask which allows free access of the water to a small well
in the glass spigot.

When the trap is working, this well opens immediately under
the hole at the bottom of the flask, and into this the organisms
can enter freely. When desiring to fix the catch, give the spigot
a slight turn the mouth of the well then presses against the side
of the cylinder and the contents become locked in.

To set the trap, fill the flask with pond water, cover the entire
funnel-shaped flask with some light-proof material, and direct all
the light that can be gathered by a bull's-eye on to the cylinder
winch contains the glass spigot. Any swimming phototactic
organism in the water will at once react and pass into the well,
which is brightly illuminated usually 10 to 15 minutes is
sufficient to allow for this, but longer time can be given if
necessary. Give the spigot half a turn, and, as already explained,
this locks the creatures in the well. The water can then be
poured off from the flask, the spigot withdrawn, and the rotifers
or whatever may have been trapped in the well can be taken
up with a pipette and transferred to the slide for examination.

After the first catch has been taken the trap can be set again and
a second lot secured. Work can therefore be carried on without
interruption or loss of time until all the water has been dealt with.

Should there be any sediment, this can be allowed to settle and
then trapped off before any attempt is made to catch the organisms.

There is difficulty in obtaining this trap made in glass ; I have
therefore worked out another in metal (fig. 3). This consists of
a round box, 1 inch in depth, 3| inches in diameter the top and
bottom slightly convex mounted on a tripod. A hole in the
bottom allows the water to pass through a short tube, which is in
three sections, the first part metal, the second rubber and the
third glass. A pinch-cock can be applied to the rubber con-
nection, which will prevent water passing when the glass tube
has been removed for examination of contents.

280 S. C. AKEHURST ON A TRAP FOR FREE-SWIMMING ORGANISMS.

I have departed from the funnel shape making the metal
box to hold the water almost flat, which will allow any sediment
to settle at the bottom. If the water is very muddy, a cork can
be fitted into the outlet hole and left until the debris has settled
first filling the tube with clean pond water.

If the cork is carefully removed, very little, if any, dirt will
pass down the tube. Should some slip by, this can be trapped
off, the tube refilled with water, when a perfectly clear gathering
can be secured.

A strainer is provided, to be used, when necessary, for removing

Fio 3.

larvae or any of the entomostraca. It is important, that as much
light as possible should be concentrated on the glass tube.

To arrange for this a bi-convex lens 1| inch diameter, silvered on
one side and mounted in a metal holder with a movable support
allowing it to be tilted at an angle, is placed under the tube, light
from a bull's-eye condenser is received by the lens and a bright
beam passed up the tube. This method of transmitting the light
is very effective, and the trap in consequence acts more rapidly
and effectively than when the bull's-eye condenser only is em-
ployed. The lens placed in position is shown in the illustration.

Journ. QueketL Microscopical Club, Ser. 2, Vol. XII. , No. 74, April iyi4.

281

AN IMPROVED FORM OF CHESHIRE'S APERTO-

METER.

By Edward M. Nelson, F.R.M.S.

(Exhibited and described by James Grundy, F.R.M.S., October 28th, 1913.)

Fig. 4.

Of the value of Mr. Cheshire's form of Apertometer there can be
no doubt. The aim of Mr. Kelson has been to enable the N.A.
of an objective to be read on the Apertometer with greater ease
and accuracy.

Distinctness and clearness of reading have been effected by

APERTOMETER OlAGRAM
/S. - 1 >nch.

(ffcfj)

Fig. 4.

increasing the number of marked values of N.A. from 9 to 22,
without the confusion that overcrowding of the lines would entail.
To accomplish this, short arcs of circles are used instead of whole
circles. A valuable property of these is the clear visibility of the
ends or edges of the arcs ; they are seen more distinctly than
complete circles would be. The contrast between the white
ground and the short black lines favours this.

The exterior edges of the arcs denote the N.A., and thus give
most convenient, accurate and definite positions for reading.

282 E. M. NELSON, AN IMPROVED FORM OF CHESHIRE'S APERTOMETER.

The first or lowest marked value is 0'05 N.A., and the values
increase by increments of 0'05 up to 0'5 N.A. From 0*5, the
values increase by 0*033 up to 0*9 N.A.

The apparatus consists of an Apertometer diagram (fig. 4)
printed on a small card about the same size as Mr. Cheshire's
form, another card of explanations and instructions, a cubic inch
of wood and a metal diaphragm with a hole not more than
1*25 mm. in diameter. Mr. Nelson lays some stress on the hole
in the diaphragm being not more than 1'25 mm. in diameter.
He says: "If the hole is larger than that, some objectives,
especially low powers, will read a great deal too high. And
accuracy is, relatively, more important with the small apertures,
because for example an error of O'Ol or 0*02 will make a far
greater percentage of difference than it would with, say, the
N.A. of an oil-immersion objective. If 1*25 and 1*27 be com-
pared with the N.A. 0*11 and 0*13 of a 3-inch objective, the
actual difference between the two pairs of values is 0*02 in each
case, but the percentage difference with the higher N.A. is only
1*6 as compared with 18 in the case of the low values."

In this connection, Mr. Nelson has made another important
remark, namely, " The working aperture is larger than the
correctly measured true aperture, so that low powers resolve more
than they are entitled to theoretically. This is probabhy due to
the practically enlarged aperture caused by the rolling motion
of the eye from side to side."

It will also be noticed that the diaphragm to be used with the
apertometer is made convex on one side, and if the convex side
is put into the larger aperture of an eye-piece or other
diaphragm, it rests steadily in position.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII. , Ko. 74, April 1914.

28

n

TWO SIMPLE APERTOMETERS FOR DRY LENSES.

By Frederic J. Cheshire, F.R.M.S.

{Read October 2$th, 1913.)

Figs. 5 amd 6.

In dealing with questions of apertometry it is very important to
inquire, in the first place, as to what order of accuracy it is
desirable to work. No useful purpose would be served by giving
a carpenter a foot-rule, divided to hundredths of an inch, with
which to measure the length of a plank. The measurement,
if made to such an order of accuracy, would be useless and
meaningless.

Prof. Abbe, in " Some Remarks on the Apertometer" {Journal
of the Roy. Jlic. Soc. 1880, p. 20), after stating that the error of
measurement in his well-known apertometer is limited to about
| per cent., goes on to say that "an exactness of reading
to this extent is evidently more than sufficient. An unavoidable
amount of uncertainty resulting from the nature of the object,
and many other sources of slight error, will always limit the
real exactness of observation beyond 1 per cent, of the unit,
different observers and different methods of equal reliability
being supposed. In low powers slight variations in the length
of the tube, in high powers slight alterations of the cover-
adjustment, will admit of much greater difference than the
error of reading will introduce. It should be observed that
in high-angled objectives the aperture has not the same
value for different colours, owing to the difference of focal
length (or amplification), even in objectives, which are perfectly
achromatic in the ordinary sense. In the case of very large
angles, the aperture, angular or numerical, will be greater for
the blue rays than for the red, generally by more than i per
cent. Last, not least, there is no possible interest, either
practical or scientific, appertaining to single degrees, or half

284 F. J. CHESHIRE, TWO SIMPLE APERTOMETERS FOR DRY LENSES.

degrees, of aperture angles ; for no microscopist in the world will
be able to make out any difference in the performance of objec-
tives as long as the numerical apertures do not differ by several
per cent., other circumstances being equal."

" For these reasons I consider all attempts at very accurate
measurements of this kind to be useless."

No one, probably, is likely to have the temerity to question
the authority of Prof. Abbe on such a question as Apertometry,
so that we can accept his limit of 1 per cent, with confidence.

Fig. 5 shows a plan of a form of apertometer for dry lenses
which for simplicity in use and for the accuracy of its results
probably leave nothing to be desired. A strip of vulcanite A *
is so divided that the distance D of any line from the zero of the
scale is given by the equation

D = 2 A tan (sin-i n.A.)

set out in this Journal for April 1904 (Ser. 2, vol. ix. p. 1), in
the article on " Abbe's Test of Aplanatism, etc." The graduations
are marked with the corresponding N.A. values for a value of A
equal to 25 mm. In use the apertometer is placed upon the
.stage and the object plane of the lens to be tested adjusted at a
height of 25 mm. above the plane of the scale. The upper focal
plane of the objective is then observed in any known way and the
apertometer adjusted on the stage until the inner edge of the
fixed white block B is seen on one edge of the objective opening.
This adjustment effected, the sliding white block C is slid along
the strip A until its inner edge is seen on the opposite edge of the
objective opening to that on which the block B is just seen.
The N.A. value found opposite to the inner edge of the block
on the scale is that of the lens tested.

The graduations from to 0*9 N.A. proceed by steps of 0*02
and from 0-9 to 0*96 N.A. by steps of 0-01.

Fig. 6 shows a modification of the form of apertometer
described in my original paper in 1904. I have substituted for
the concentric circles there shown curved lines which project
optically into the upper focal plane of the lens being tested as a
number of equi-distant straight lines of equal thickness. The
projected image of the apertometer scale is thus a simple linear

* The right-hand end is shown broken off.

o

6

II
<l

U
h

-

o

<r
ai
a
<

en

a

I

00

UJ

I

O

O

QQ

286 F. J. CHESHIRE, TWO SIMPLE APERTOMETERS FOR DRY LENSES.

scale upon which N.A. values can be read directly. The scale
runs from 00 to 0*9 N.A. by steps of 0*05, i.e. the divisions
starting from the centre have the values 0, 0'05, 0"10, 015, - 20,
etc., of N.A.

The short curved lines of the scale should strictly be hyperbolas,
but such curves are very difficult to draw accurately, and it was
not until my son, Mr. R. W. Cheshire, suggested to me that they
might be replaced by arcs of circles with curvatures equal to
those of the corresponding hyperbolas at their vertices that the
apertometer described became a practical construction.

I may, perhaps, be allowed to avail myself of this opportunity
to say that in my opinion there are several objections to
Mr. Nelson's form of the Apertometer which was introduced
by me in 1904. These may be briefly indicated. In the first
place, no advantage can result from the use of the outer edges
of the lines, instead of the middles, as is usually done, as the
part of the lines from which distances and therefore NA.'s
must be estimated by eye. Further, in Mr. Nelson's form the
thickness of the lines varies in different parts of the diagram,
and has no assigned or stated thickness in terms of N.A. This,
I think, is a fatal defect, because when the thickness of a line
has a N.A. value of - 02, say, such thickness, especially when
dealing with low-power lenses, provides an invaluable standard
of reference when estimating by eye N.A. values intermediate
to those represented on the scale.

In apertometers of the kind in question the further the sub-
division of the scale is carried the greater must be the complexity
of the image presented to the eye the advantage of one is
balanced by the disadvantage of the other. Possibly, however,
most people would prefer the simplicity of a diagram with the
larger divisions to the optical Hampton-Court-maze necessitated
by the smaller ones.

Joum. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914.

287

A VARIATION OF CHESHIRE'S APERTOMETER.

By M. A. Ainslie, R.N., B.A., F.R.A.S.
.(Read October 2Sth, 1913.)

Figs. 7 and 8,

Experience in the use of both the original forms of Cheshire's
Apertometer, and the modification thereof recently introduced
by Mr. E. M. Nelson, has revealed one or two difficulties in
connection with the reading of the instrument that is, if any
accuracy in the second place of decimals is required and the
present instrument is an attempt at removing these.

The first difficulty is due to the fact that in Mr. Cheshire's
instrument we have to interpolate or estimate between two
divisions on a scale, one of which is not visible, being outside
(apparently) the margin of the back lens of the objective, This
renders the estimation of the second place of decimals in the
N.A. uncertain, and although Mr. E. M. Nelson's modification
of the original instrument is somewhat better in this respect
yet the very means adopted to improve the reading, namely,
the introduction of a large number of additional circles is
likelv to confuse the diagram and bewilder the observer.

In either the old form or the new of Cheshire's instrument,
a count has to be made of concentric circles ; a thing which,
simple as it may seem, is peculiarly liable to confuse the eye ; so
that it is only after counting several times that one feels certain
that the number is, say, eight and not seven. In the present
instrument a totally different method of reading is adopted ; the
diagram is simplified, and the estimation of the second place of
decimals is merely the estimation of the point where a spiral
curve cuts the margin of the back lens of the objective, referred
to two points, one on each side, where radial lines cut the
same.

The instrument, which consists, in the form for dry lenses,

288 M. A. AINSLIE ON A VARIATION OF CHESHIRE'S APERTOMETER,

of a card diagram placed on the stage, is constructed as follows-
(% 7):

A series of radial lines are drawn from a common centre,
making equal angles with one another ; the precise number is-
immaterial, but it has been found convenient to divide the circle
into sixteen equal parts. One of these (preferably that lying^
horizontally) is selected as a zero, and points are marked off
along the others at distances equal to a constant length (usually
25 mm., or 1 inch) multiplied by the tangent of the semi-angle
of aperture ; i e. the tangent of the angle whose sine is the-
numerical aperture. This is done for every (H of N.A., and
a spiral curve drawn through the points thus obtained ; this.

Fig. 7.

curve being repeated, turned through 180. The curves are
shown with fair accuracy in fig. 7.

The diagram is used precisely as the Cheshire Apertometer :
either the objective is focused on the upper surface of a cube of
wood as in the Cheshire instrument ; or else a pinhole in the
centre of the diagram is focused, and the body racked back
25 mm., or 1 in., this being measured easily enough with a
scale. This latter method is preferable for objectives of high
aperture. A |low-power eye-piece is employed. On examining
the Ramsden disc with a hand lens (a watch-maker's eye-glass
does well) the appearance in fig. 8 is seen, and the method of
estimating the value of the N.A is fairly obvious ; we have only
to start from the zero and count in the direction of the spiral,

M. A. AINSLIE ON A VARIATION OF CHESHIRE'S APERTOMETER. 28i>

(H for each radial line passed over ; the second figure is found by
estimating the position between two adjacent radial lines of the
point where the spiral cuts the margin of the back lens. In
tig. 8, for example, the N.A is about - 73.

The procedure is the same with the form suited to immersion
lenses ; the upper surface of a plate of glass is focused, and the
diagram is balsamed to the lower surface. It might be pre-
ferable to have 12 radial lines instead of 16, and read like
a clock ; this is a matter for experiment.

Of course the value of the radius vector of the curve for
a diagram in optical contact with glass will not be quite the
same as before ; instead of r = C tan <, where sin < = N, we

8

Fig. 8.

shall have r = C tan <' where /x sin <' = N\ but the principle

is the same.

The equation to the curve presents some interesting features;

aO

where C is the distance of the diagram

it is r = Cr_

V 1 a 2 2

from the lower focal plane of the objective and a is a constant
depending on ll and on the number of radial lines in the circle ;

for 16 radial lines, and /x = 1 (dry form), a = ^ . The radius

representing N.A. = I/O is obviously an asymptote to the curve ;
in the case of the glass form, N.A. = /x will be the asymptote.

It is of interest to note that the same curve will serve for any
refractive index of the medium beneath which it is mounted : if

290 M. A. AINSLIE ON A VARIATION OF CHESHIRE'S APERTOMETER.

we change the refractive index from 1 to ju, we merely have to
close up the radial lines in that ratio, leaving the curve unaltered.
For instance, if we had 16 radii for the dry form we could use
the same curve, but with 24 radii, for a plate of glass of
fx = 15.

In practice the instrument proves of great utility, and very
reliable and easily used. All that is necessary is to be accurate
in centring ; this is easily seen to be correct when the reading of
each end of the spiral is the same.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914.

291 AfclC

ON THE DISC-LIKE TERMINATION OF THE
FLAGELLUM OF SOME EUGLENAE.

By James Burton.

(Bead November 25th, 19130

About two years ago, one of our members Mr. Ellis was
exhibiting here living Euglena viridis. During the evening the
creatures, presumably affected by the light, heat and confine-
ment of the life-slide, threw off their flagella ; it was perhaps a
preparatory step to encystment, or even to their death, under
the unnatural conditions of their environment. In the field of
the microscope there were numbers of these organs floating
free, and in the case of many of them, if not quite the ma-
jority, they were terminated by what appeared to be a small
disc or bulb. We were greatly interested in the phenomenon,
and decided to investigate it. Mr. Ellis soon after wrote a
letter to The English Mechanic, describing what he had seen, and
inquiring if any one else had had a similar experience. There
were no very definite answers, no one claiming to have noticed
this occurrence before. In his letter he says :

" On turning on the one-sixth, something quite out of the
ordinary at least, to me was seen in the shape of minute
transparent discs, each with a long, thick, but motionless fla-
gellum, and apparently associated with the resting Euglenae,
around which they appeared most plentiful. For some time I
was puzzled to account for these objects, until, noting the
obvious similarity in length and thickness between their flagella
and those of the motile Euglenae, I became convinced they were
one and the same, they having been thrown off* bodily by the
exhausted Euglenae, and not retracted as is usual, I under-
stand." . . . " Now here comes the difficulty : What is the little
disc to which the flagellum is attached ? Is it the ' knob-like
inflated distal extremity ' of a flagellum belonging to 'an interest-
ing local variety of E. vi?'idis' described by a writer in Science
Gossip for October 1879, and referred to by Saville-Kent on
p. 382 of his ' Manual of the Infusoria,' and illustrated on

Jourx. Q. M. C, Series II. No. ~. 21

292 J. BURTON ON THE DISC-LIKE TERMINATION OF THE

PI. xx. fig. 29 ? " Saville-Kent says, in the paragraph referred to :
" An interesting local variety of E. viridis has been recently
described by Mr. M. H. Robson, of Newcastle-upon-Tyne, in
which the distal extremity of the flagellum presents an inflated
knob-like aspect, as shown at PI. xx. fig. 29. Possibly such
modification of this important organ represents a phase pre-
liminary to its entire withdrawal, and antecedent to the
entrance of the animalcule upon the encj 7 sted or resting stage."

In Science Gossip (1879) there are several letters about the
phenomenon, one on p. 231 by Mr. Robson, with the original
drawing from which Saville- Kent's figure is taken, and also two
other forms of Euglenae with identical organs. Referring to
them, Mr. Robson says: "These may be of interest, as I, at all
events, have not met an observer who has previously noted this-
peculiarity." In a letter on p. 136 another writer mentions a
case where in a large number of Euglenae " the flagellum was in
each case bulbed." And he draws the singular conclusion that
these were not true Euglenae, but suggests they may have been
a larval form of the rotifer Hydatina senta. In a letter, p. 159,.
Mr. Robson writes of E. viridis and its " sucker bulb," and of the
existence of " the bulb siphon, sucker, or whatever it is." On
p. 256 there is a letter from Mr. George headed, " E. viridis and
its bulbed flagellum," and he makes reference to the fact that
" on one occasion, whilst closely watching the contortive move-
ments of a full-grown specimen, I was much surprised to see the
little animal ' bite off",' if I may so term it, the flagellum, which
immediately floated away." It is clear at least from all this that
observers a good many years ago saw the structure, and that it
created a good deal of interest and some speculation as to the true
interpretation of the appearance.

Now, to return to Mr. Ellis's question, " What is the little
disc " attached to the distal end of the flagellum of some
Euglenae ? After some considerable attention to the subject,,
and observation of many examples, I have come to the conclusion
that there is no disc, no bulb or sucker, or anything of the kind
at the end of the flagellum. The appearance which has given
rise to the idea can be correctly accounted for in another
manner. I have often seen the disc since Mr. Ellis first called
attention to it, but do not remember ever seeing it on a flagellum
in active use by a healthy Euglena ; in fact, it is almost impos-

FLAGELLUM OF SOME EUGLENAE 293

sible to see the flagellum at all when the creature is in full vigour
it is then usually being lashed about, and is bent and twisted in
all directions. It will be noticed that Mr. Ellis only claims to
have seen the disc when, for some reason, the organ to which it
was attached was thrown off.

He says : " Out of all the numberless motile Euglenae which
were swimming about amongst their resting kindred, not one was
seen with a flagellum having a knob at its free extremity."

Neither do I think any of the writers in Science Gossij) dis-
tinctly claim to have seen it on a healthy, active animal. But
when the flagellum is thrown off " bitten off," as has been
described or when the Euglena is killed by a careful application
of iodine, it is not at all infrequent, and I have seen it on speci-
mens from many different localities.

It happened that since I thought of bringing the subject
before you I was looking over, for quite another purpose, a slide
of Euglenae mounted in April 1911. I there found several
instances of discs still attached. Some creatures, and some
Euglenae at all events, occasionally carry the flagellum stretched
out rigidly in front, with a small portion of the distal end thrown
into a coil or spiral form, usually rapidly moving. Now if the
creature were killed with the organ in that position, or for any
reason threw it off, it seems to me very probable that the coil
there might be but one turn in it would present just the
appearance we have had referred to as a disc or bulb, and that,
consisting of protoplasm, it would be very likely to adhere where
touching another part, and so retain its form as a circle. With
the use of an immersion objective and careful illumination, it has
seemed to me possible to make out a part of the circle as being
thicker or darker than the rest, owing to the thread overlapping
at that point. It must be remembered that we are dealing with
a very small and very transparent structure, not easy to demon-
strate correctly. Moreover, among the others, killed by iodine
or mounted, it is easy to find specimens with the flagellum much
twisted and thrown into " kinks." So that there are often small
circles at the sides instead of at the end of the thread, and
although these have just the same appearance as those at the
end, I do not think any one would suggest that it is likely a disc
or bulb would occur in such a situation, to say nothing of the
im probability of there being more than one, and these often on

294 J. BURTON ON THE FLAGELLUM OF SOME EUGLENAE.

opposite sides. These would be put down at once as loops or
kinks and I believe the so-called terminal disc or bulb is of the
same nature, but it is more striking and more deceptive, owing
solely to its position. When I told Mr. Ellis of the conclusion I
had come to, he was at first disinclined to accept it, but after-
wards, I think, did so fully. If I am right, the subject is merely
an instance of correct observation but incorrect deduction from
it in fact, an error of interpretation, quite a well-known occur-
rence to microscopists ! Perhaps, indeed, the matter would hardly
justify particular reference to it, had not the figure and the note
read appeared in Saville-Kent's Manual a work whose value to
us all gives it an importance and authority which must be my
excuse.

Joura. Que/cett Microscopical L'lub, Ser. 2, Vol. XII , A'o. 74, April li'14..

205

ON THE MEASUREMENT OF THE INITIAL MAGNI
FYING POWERS OF OBJECTIVES.

By Edward M. Nelson, F.R.M.S.

{Read November 25th, 1913.)

Fig 9.

The majority of uiicroscopists only concern themselves with the
total magnifying power of their microscopes, but some wishing to
probe further into matters want to know the initial power of their
objectives.

The initial magnifying power, m, of an objective is -7-, but the

focal length (f) of an objective is a very difficult thing to measure
directly. Usually it is found by an indirect method of measuring

the magnifying power, for, as above, = /.

Probably the best way of measuring the focal length by the
indirect method is to project the image of a measured object,
placed 100 inches from the stage, and to measure the diminished
image at the focal point of the objective by means of a microscope,
fitted with a screw micrometer ; the magnification, m, thus
obtained will give the focal length with great accuracy, for

f ~ z. As the numerator is 100, the result can be found in

nt 4- 'Ji

a reciprocal table, without the necessity of doing a division sum.

Simple as this seems, it is however a troublesome thing to do ;
but by the method here described the initial power, and hence the

296 E. M. NELSON ON THE MEASUREMENT OF THE

equivalent focus of a microscope objective, can be quickly and
easily measured.

The apparatus required is a stage micrometer and a screw
micrometer with a positive eye-piece. With a tube of a length
as described below, the interval of two divisions of the micro-
meter scale on the stage is read on the drum of the eye-piece,
and this reading will be the initial magnifying power of the
objective.

The only difficulty here is the determination of the proper
tube length. The tube length is to be measured from the
web in the eye -piece to the end of the nose-piece of the
microscope.

The formula for the determination of the tube length is

15 \/ - -f- 0335, where p is the nominal initial power. Example:
V

The initial power of a half-inch is required. The nominal
power of a half-inch is 20, which is p, then 15 A/ + 0*335 =

15v/0-385 = 15 x 0'62 = 9*3 inches tube length.

The tube must be drawn out until the web is 9 - 3 inches from the
nose-piece, and, with the half-inch on the nose-piece, two y^^ths
of an inch divisions on the stage micrometer are spanned by the
webs. The drum then is read, say, 22*4, and this is the initial
power of that half-inch, without any further calculation; its focal

length is ip^ ov Q'^Afi inch.

In case the nominal initial power is unknown, it is first deter-
mined with, say, a 9^-inch tube, the value thus found is inserted
in the equation and the measurement made again with the
correct tube length. All powers of quarter-inch and less focus, all
Zeiss's apochromats of whatever focus, and other makers' apoch-
romats, require a 9-inch tube.

INITIAL MAGNIFYING POWERS OF OBJECTIVES.

297

For lower powers the accompanying table, computed by the
above formula, gives the necessary tube length.

It must be noted that it has been assumed that the screw
micrometer with the positive eye-piece is an English one, with
50 threads to the inch, but if it is a Continental one, with a
millimetre thread, a millimetre stage micrometer must be used,
and the proper number of divisions measured. If it is found that
the magnification is so high that two divisions cannot be spanned
by the micrometer webs, then obviously one division is measured
and the reading is doubled.*

TABLE.
0, objective ; N, nominal power ; T, tube length in inches.

N

T

O

N

T

o

12-3

1

10

9-9

3

3-5

11-8

3
4

12

9-7

4

11-5

2
3

15

9-5

4-5

11-2

1
2

20

9-3

2

5

11-0

4

25

9-2

5-5

10-8

1
7J

30

9-1

6

10-6

35

9-05

1|

7
8
9

10-4
10-2
100

1

40

9-0

Let me again impress upon microscopists to measure, or get
measured, the optical indices of their objectives. The optical
1000 N.A.

index is

m

Photographers have the same thing in their

//4, //16, etc. No photographer would think of paying as much for
a lens of f/lQ as he would for one, of similar focus and qualitv, of
fji) then why should a microscopist? A microscopist, for example,

The foci of a large number of all sorts of microscope objectives, which
had been previously accurately determined by the long method, were
remeasured by this new short method ; the results obtained were so
satisfactory that now only the short method is used.

298 E. M. NELSON ON THE MEASUREMENT OF THE

buys a T *oth objective of 0"65 N.A. Here an optical index of 26 -
is implied ; when he gets home he measures it and finds it |rd of
055 N.A. with an optical index of only 18*3, or 30 per cent. less.
This is not an exceptional case, but one which unfortunately
exemplifies the usual practice. Messrs. Zeiss have for long set an
excellent example by never sending out lenses below either their
catalogued N.A. or shorter foci. I have measured scores of them
and have found their optical indices often in excess, and seldom
if ever in defect.

[The method of determining the focal length of an objective,
by the indirect method from the magnifying power, may not be

A

t

B

L too inc\e& _^

i

c

Mr

r

s

Fig 9. Diagram to show Relative Positions of the Apparatus.

M Microscope tube. P> Objective.

A Screw micrometer. C Objective to be measured, in substage.
S Microscope stage and micrometer.

quite clear, hence the following particulars from notes received
from Mr. Nelson may be useful. His own words are practically
as follows: The microscope is placed horizontally; a low- power
objective, 3, 2, or 1| inch, according to circumstances, is placed
in position ; screw-micrometer eye-piece ; the objective to be mea-
sured is placed in substage, with its front lens facing the stage.
A card cut to the pattern as shown in figure (fig. 9) is fixed by
means of a clip in front of the window : the card should be
placed at the exact measured distance of one hundred inches
from the stage of the microscope.

INITIAL MAGNIFYING POWERS OF OBJECTIVES. 209

The stage micrometer is placed on the stage, and the constant
of the screw-micrometer determined. The focus of the micro-
scope is not to be disturbed, but, by means of substage focusing,
the lens to be measured is racked up until the image of the card
is sharply focused. Then one of the sides of the card is spanned
by the webs of the eye-piece micrometer, and its size measured
and the magnifying (or rather diminishing) power found : then

._ 100
~~ m + '2'

Of course, the idea of the 5 inches is that the reading is

doubled, and then 10 -t- x (say), gives the magnification, m, which

can be found from reciprocal tables, as well as the value of

^ ' 1,1 + T

It is not difficult, but a little more trouble, to make the calcu-
lations without tables.

For the benefit of photomicrographic members, the following
is quoted from a note by Mr. Nelson. " This method will
measure the foci of large photographic lenses. In that case

,_ 100 _ 100

m + 2 (m + If

" This second term is only necessary when f is large compared
with one hundred inches ; for microscopic lenses it is not wanted.
The whole can be determined from reciprocal tables without
putting pencil to paper." The tables referred to are those of
Barlow, published by Messrs. E. & F. N. Spon.

The screw-micrometer eye-piece is, perhaps, a drawback. Mr.
Nelson says, "An ordinary screw-micrometer with a negative
eye-piece is no good for lens measurements ; the eye-piece must be
of the Ramsden type, and it is very doubtful if any ordinary
ruled glass micrometer eye-piece would be sufficiently accurate.
A screw-micrometer is necessary for both the methods described
in the paper."

300 E. M. NELSON ON INITIAL MAGNIFYING POWERS OF OBJECTIVES.

It will be noticed that Mr. Nelson lays stress on what he has
named the Optical Index ; but perhaps it is less apparent that
this paper on the magnifying power of objectives, and his com-
munication to the last meeting on their aperture, are quite
closely related to the Optical Index in fact, they deal with both
the values involved in the formula for the Optical Index of an

, . .. Numerical Aperture x 1,000

objective = A ^ .

Magnifying .rower

A general way of expressing the meaning of the Optical Index

of an objective is that it is the ratio of its aperture to its

power. J. Grundy.]

Joura. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914.

301

SOME OBSERVATIONS CONCERNING SUB-STAGE

ILLUMINATION.

By S. C. Akehurst, F.R.M.S.

(Bead January 27th, 1914.)

Plates 20-22.

The accepted method, and the one generally used, for sub-stage
illumination is that known as the solid cone of light, controlled,
within certain limits, by the iris diaphragm. Another form that
is, annular light is occasionally used, but is not considered by
many microseopists to be of value for critical work.

Both these forms of illumination are too well known to need
detailed explanation. The textbooks, however, have very little
to say either for or against the latter method, excepting Cross and
Cole, 3rd edition, where a definite statement in favour of annular
light is to be found. I cannot do better than quote this : " Stops
can be further used for strengthening the contrast in the image
with large cones of illumination and objectives having high
apertures. This method does not minimise in any way the
effective working of the objective, for, with objectives of large
aperture, rays may be present which only impart brightness to
the field, but do not contribute to making visible the fine detail
upon the object. If less than half of the lateral spectra are seen
on looking down the tube at the back lens of the object glass with
a striated object in focus, then the central portion of the direct
beam or central disc has no lateral image corresponding to it in
the portions of the spectra that are visible. Under these circum-
stances, that central portion of the central disc in no degree
contributes in enabling the detail to be seen, but only produces a
haze ; by blocking it out the haze is removed and there is a great

302 S. C. AKEHURST ON SOME OBSERVATIONS CONCERNING

improvement in the resulting definition." Mr. J. W. Gordon's
opinion is that when a suitable stop is employed in the sub-stage
condenser there is no objection to using annular light with an oil-
imniersion objective of high numerical aperture. It is, however,
necessary that the outer zones of the objective used should be
well corrected. His own method of blocking out the central
beam is to use a stop over the eye-piece and this is fully described
in the Journal R. M. S., February 1907. On the other hand,
Carpenter does not entirely agree that annular light is permissible.
Quoting from the seventh edition, he says, " If it is required to
accentuate a known structure, such as the perforated membrane of
a diatom, it can be done by annular illumination, which means
the same arrangement as for dark-ground but with a stop insuffi-
ciently large to shut out all the light. This method is not to be
recommended when a structure is unknown, as it is also liable to
give false images."

Mr. Nelson has also expressed himself against annular light,
stating that whilst strong resolution of diatoms is obtained by
this method of illumination it also gives rise to spurious images.

The subject of sub-stage illumination is a large one, and I am
only dealing with one phase of it, viz. annular light produced by
a reflecting condenser, to be used in conjunction with an oil-
immersion objective, for resolving the fine structure of diatoms
and displaying stained bacteria.* When a wide-angle refracting
condenser is employed, with stop to produce annular light, trouble
arises through chromatic aberration, which is especially noticeable
when an objective of high aperture is used. This dispersed colour
is objectionable, as it operates against a pure image being formed,
and is also detrimental to obtaining faithful records by photo-
graphy. Much has been undertaken to demonstrate that, in
practice, light from a condenser exhibiting chromatic aberration

* A slide of Tubercle bacilli was exhibited illuminated with annular
light, showing that the reflecting condenser works well with small stained
objects in addition to diatoms.

SUB-STAGE ILLUMINATION. 303

does not prevent good work being accomplished. On the other
hand, I believe the reduction of chromatic dispersion to a minimum
leads towards an ideal system for critical work.

The question now arises, if annular light is employed with
objectives of high aperture, how is the trouble arising through
chromatic aberration to be avoided. I suggest reflected, instead
of refracted, light being used. I came to this conclusion after
makincr a number of observations with a Leitz concentric reflect-
ing condenser. This condenser has two reflecting surfaces, one
convex and the other concave, and, as the rays are brought to a
focus by reflection only, there is no chromatic dispersion, and
spherical aberration is reduced to a minimum. The elimination
of spherical aberration, however, is not a matter of importance.
This was pointed out to me by Mr. J. W. Gordon, who has very
generously allowed me to make use of his remarks on this point.

He says: "Light from the periphery of the condenser may
exhibit defects due to spherical aberration. This light, on reach-
ing the object, sets up a new impulse, and the rays emerging from
the object, and travelling towards the eye, will, in any plane con-
jugate to the plane of the stage, appear free from the original
defects of spherical aberration just as if they had started from
an independent source. No false images would, therefore, arise
from this cause in the image plane when light is used from a
sub-stage condenser that has not been corrected for spherical
-aberration." It should be carefully noted that this reflecting con-
denser was produced to obtain dark-ground effects, and was never
intended to be used in the manner I have employed it that is, in
conjunction with a T V inch oil-immersion objective without a funnel
stop to reduce the IS". A. of the objective. In its present form the
reflecting condenser I have passes too much light. The results
obtained, however, were sufficiently striking to arrest attention
when resolving fine structure of various diatoms. The transverse
striae of Amphlpleura pellucida in monobromide of naphthalin
were displayed. In realgar the same details were strongly shown,

304 S. C. AKEHURST OX SOME OBSERVATIONS CONCERNING

and when the mirror was slightly tilted, if the diatom was a
suitable one. it was resolved into dots. A good image of the
rosettes on Coscinodiscus asteromphcdus was obtained, which
stood a high-power eve-piece well. With the mirror slightly
tilted, the faintly marked transverse striae were visible on Cymato-
pleura solea also an excellent black-dot image was displayed of
Xo.ck'da rhomboid.es, SurireUa gemma and Pleurosigma angu-
IcUuin. On examining a strewn slide of Xacicula r~homboid.es
in realgar I found a specimen of Pinnularia nobilisl On tilting
the mirror and obtaining oblique light the costae were filled with
dots. Particulars of this were forwarded to Mr. Nelson, who
replied as follows: "Mr. Merlin and I have seen the structure
on Pinnularia to which you refer. It was demonstrated upwards
of twenty years ago by H. Gill, who tilled up the apertures in
diatoms with platinum some of these specimens I have still." I
am pleased to be able to give this report, as it helps to dispose of
the idea that might arise that the dots displayed were probably
due to false images, brought about by using annular light.

The opaque lines on an Abbe test plate were well defined, and
an excellent rendering of stained bacteria, such as Tubercle bacilli,,
was obtained. In all the tests referred to the following combina-
tion was used : Incandescent gaslight, Nelson stand condenser,
Leitz concentric reflecting condenser and tiuorite, T Vth inch oil-
immersiun objective N.A. 1*35, Wiukel complanat eye-piece, and
Wratten B screen.

During the autumn of 1913 Mr. O'Donohoe became interested

in this reflecting condenser, and he spent an evening with me

examining some of the test objects referred to ; and afterwards

kindly undertook to see if any results worth attention could be

obtained by photography when using this type of condenser. He

was successful in getting a record of the dots on Pinnularia.*

I am very much indebted to Mr. O'Donohoe for the ready
manner in which he undertook the work of testing the condenser,

* T. A. O'Donohoe : "An Attempt to Resolve Pinnularia xobilis,'' p. 309.

SUB-STAGE ILLUMINATION. 305

and for the photographs which illustrate this paper ; and you
will agree with me that without these records my remarks con-
cerning the value of reflected annular illumination would have
been much less convincing.

Summary of the Advantages in using Annular Light
produced by reflecting condenser.

(1) When employing an achromatic condenser excess of light
is reduced by closing the iris diaphragm. This involves a sacrifice
of the numerical aperture, and, therefore, loss of resolution.
With the reflecting concentric condenser there is no loss of high-
angle rays, the excess of light being modified by stopping out a
portion of the central or dioptric beam; the fullest possible
advantage can, therefore, be taken of the numerical aperture of
the whole optical system.

(2) Chromatic dispersion being entirely eliminated, a pure
image is obtained.

(3) The absence of colour in the field admits of critical work
being done by photo-micrography.

(4) When necessity arises to search a slide for minute striae,
or other fine structure, it is immaterial in which direction across
the field the striae appear they are resolved.

(5) The simple construction of this type of condenser admits
of it being produced at about half the cost of an achromatic oil-
immersion condenser ; and whilst it can only be employed with a
Y2-th inch oil-immersion objective in the manner already described,
yet it gives excellent dark-ground effects with all powers from
Ygth to ^th inch.

One defect if defect it can be called is that, in its present
form, there is no method of controlling the light passed by altering
the size of the stop. It is just possible means can be devised to
allow of this being done.

In my opinion there appears to be room for a reflecting con-

306 S. C. AKEHURST ON SOME OBSERVATIONS CONCERNING

denser to be used with high-angled oil-immersion objectives, even
though the field for its usefulness may be limited.

1 hope the photographs illustrating this paper will prove of
sufficient interest to stimulate further investigation into the
value of annular light, and to demonstrate what limits, if any,
should be put upon its use.

Descriptions of Plates.
Plate 20.

Figs. 1 to 7 are illustrations of various figures of the spectra
of Pleurosigma angulatum as seen at the back lens of an oil-
immersion objective with the diatom in focus an achromatic
condenser, with and without stop, and reflecting condenser being
used. Pigs. 1 to 3 are of no special interest just now most of
you are familiar with these diffraction spectra, varied according
to the diameter of the opening in the iris diaphragm.

Fig. 1 shows result obtained with the diaphragm almost closed.

Fig. 2 the diaphragm is opened so that one-third of the back
lens is in shadow. The details of the diatom are hardl) T per-
ceptible, being flooded out by excess of light.

Fig. 3. The iris is closed, until two-thirds of back lens is in
shadow. In this position, with the spectra just touching the
edge of the central beam of light, the best resolution of Pleuro-
sigma angulatum is obtained.

Fig. 4 shows the spectra obtained when a large spot is used.
The six diffraction spectra forming the symmetrical image should,
however, be slightly moved from the centre outwards to reduce
the diameter of the hexagonal spot in the centre, which in the
drawing is a little too large. In this instance insufficient light
was passed, and an unsatisfactory image of the diatom was dis-
played. My next spot being too small, the picture of the spectra
obtained is as shown by flg. 5. Here Ave have six dark cuspidate
forms, disposed as a six-pointed star, the intermediate spaces
being filled with a diffused light, the whole figure being some-

SUB-STAGE ILLUMINATION. 307

what ill-defined. This effect was due to an excess of light ; by
slightly closing the iris diaphragm the light was reduced, and we
have the result as shown in fig. 6 the symmetrical design well
defined on a black ground, and just a glimpse of another portion
of the spectra at six points round the shadow caused by the partly
closed diaphragm. With the spectra showing, as illustrated in
fig. 6, I obtained the best definition of Phurosiyma angulatum
with achromatic condenser and spot.

Fig. 7 is the record of the spectra obtained of the same diatom,
using the reflecting condenser ; the similarity between the figures
7 and 5 is noticeable.

My reflecting condenser to work at its best when using it for
annular light requires the light cut down until a crisp image is
shown of the spectra as at fig. 6.

Fig. 8 represents the rulings on an Abbe test plate, as displayed
by T V inch oil-immersion objective and reflecting condenser. The
position of the light bars is to be noted : there are six those at
the top and bottom are not quite fully displayed. On first
examining the back of the objective I observed the two rows
of six white dots, as shown at fig. 9. At another examination
the light probably being more central I found an almost com-
plete circle, as at fig. 10, made up of ten white clots on each side
and a thin streak of light at the bottom. I have not yet been
able to put forward a suggestion as to how these are formed.
I have, however, included them in my record, as they may be
of some interest.

Plate 21.

Fig. 1. Nitzschia linearis x 2,500, showing the white-dot image.
This photograph was taken with a highly corrected oil-immersion
condenser and axial illumination.

Fig. 2. Nitzschia linearis x 3,000, this time showing the
black-dot image. This photograph was taken with reflecting
concentric condenser.

Journ. Q. M. C, Series II. No. 74. 22

308 S. C. AKEHURST ON SUB-STAGE ILLUMINATION.

Both these pictures were taken by the same man, using the
same objective, diatom and illumination the only difference
being in the condenser used. Regarding this matter, Mr.
O'Donohoe writes as follows : " I was never able to see the
black-dot image when using my ordinary oil-immersion condenser,
hence was much surprised to find that the reflecting concentric
condenser showed the black dots beautifully. This and the
Amphipleura show that the reflecting condenser is a better re-
solver than my ordinary oil-immersion condenser and axial
illumination.

Fig. 3. Amphipleura pellucida x 2,000. This photograph was
taken to demonstrate the usefulness of annular light when
searching a slide for fine structure. The diatoms are at right
angles to each other, and both resolved. Had light in one
azimuth been employed, such as one gets with an achromatic
condenser, and quarter-moon stop, only one would have been
resolved, viz. the diatom with striae at right angles to the
direction of the beam of light.

Fig. 4. A record of Surirella gemma x 2,000. This was
taken with the reflecting condenser. The black dot is shown,
and at the same time the ribs are resolved into dots.

Plate 22.

Fig. 1. Navicida rkomboides x 1,500, taken with the re-
flecting condenser.

Fig. 2. Pinnidaria nobdis x 2,500, showing the costae filled
with dots. Taken with the reflecting condenser.

Journ. Quekett Microscopical Club, Scr. 2, Vol. XII., No. 74, April 1914.

Journ. O.M.C.

Ser. 2, Vol. XII., PI. 20.

WEW OF BACK LENS' OP OBJECTIVE

j <

PL EURO SIGMA. >- HG\J LATUM I hi FOC

JCATIC
CONDENSE ~

*fl r

ACHROMATIC

C0Ni)NSR

'.Ml Ttf

STOP

CCNCEI
REFLI

CONDE.NSER

A

u.

Jk B B e

TLiT
PLATE

C. H. Caffyn, photogr.

Journ. Q.M.C.

Ser. 2, Vol. XII., PL 21.

T. A. O'Donohoe, photogr.

Resolution with Annular Illumination.

Journ. Q.M.C.

Sen 2, Vol. XII., PL 22.

T. A. O'Donohoe, phologr.

Resolution with Annular Illumination.

o

09

AN ATTEMPT TO RESOLVE AND PHOTOGRAPH

PINNULARIA NOB I US.

By T. A. O'Doxohoe.

(Read January 21th, 1914.)

Most microscopists are acquainted with the little diatom called
Pinnidaria nobilis, which, on the test slides of twenty diatoms
mounted by Moller and Thum, takes the second lowest place,
with striae numbering from 11,000 to 12,000 to the inch.
It is just because it occupies such a lowly place that it is
passed over with contempt as being worthy of the notice only
of the babes and sucklings of microscopy who find themselves
in possession of a 2-inch or 1-inch objective.

Such was my own feeling towards it until quite recently,
when Mr. Akehurst showed me by resolution into dots that it
deserved a better fate, and invited me to resolve and photograph
it, if I could, and for this purpose he, at the same time, lent
me a realgar mount and the reflecting dark-ground condenser
of Leitz. I have since learnt that an objective and illumination
which, without any manipulation, showed me at once the striae of
Nitzschia linearis, Frustulia saxonica, and Amphiplewa pellucida,
and the very distinct black dots of all the other diatoms on
Thum's test plate of 30 forms, failed completely in inducing the
Pinnidaria nobilis on the same slide to yield up its secrets. So
that the diatom to which almost the lowest place is assigned
by the mounter is, in fact, by far the most difficult to resolve.
Examined with a drv lens of N.A. - 85 and direct cone of
light, we get an image in which on each side of the raphe
are seen two zig-zag lines running from end to end and dividing
the linger-like bands into three series or each band into three
compartments. This is all that can be seen with a dry lens.

Now using a Zeiss 2-mm. apochromat N.A. 1*3, and Watson's
Holoscopic immersion condenser, and finding a central cone of
light unavailing, I inserted the crescent stop in the condenser,
and proceeding as if I were resolving the striae of Amphiphura
pellucida, I succeeded in getting an image which shows what one

310 T. a. o'doxohoe on pin nul aria nobilis.

must call the costae, broken up into three parts, with very fine
lines between them. It may be seen that the middle parts of
the costae are in the sharpest focus because they represent the
highest of three distinct planes. Now if this interpretation be
correct, the structure of this diatom is very complex, as there
would be three planes on each side of the raphe, and the planes
on the one side would coincide with those on the other only when
the diatom was perfectly flat on the cover-glass a very un-
likely case.

I now tried to resolve the costae, with the result as shown
[here an image was projected on the screen], which reminds one
of the bones of a skeleton's hand.

There remained the resolution of the very fine lines between
the costae, probably into dots. After trying to do this many
hours without any success I substituted Mr. Akehurst's dark-
ground condenser for the Holoscopic, with the result that, after
considerable manipulation I was able to get the photograph here
reproduced. (See PI. 22, fig. 2.) This shows at least partial
resolution on both sides of the raphe.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914.

311

NOTES.

ON A METHOD OF MARKING A GIVEN OBJECT FOR
FUTURE REFERENCE ON A MOUNTED SLIDE.

By James Burton.

{Read November 25th, 1913.)

Most likely all of us at times have come across some particular
object on a mounted slide which we have felt we should like to be
able to find on another occasion ; perhaps some special diatom on
a strewn slide, for instance. Now there are several methods of
doing this, and a little piece of apparatus is sold by the opticians
which marks a circle round an object first found under the micro-
scope. But perhaps with the majority the necessity does not
occur often enough for it to be worth while to keep a special tool,
and the little dodge, if I may call it so, which is here described
can be carried out without any other instrument than those we
most of us already have and use. If the object to be marked is
sufficiently large for recognition under a moderate power, such as
can be obtained with a hand lens or dissecting microscope, the
matter is very simple. First find the object, then with a fine
camel-hair or sable brush carefully place a dot of water-colour
over it large enough to be seen with the naked eye, set it on one
side to dry ; when dry, put the slide on the turn-table with the
dot accurately in the centre and turn a small ring round it with
any dark cement you may have in use; when this is hard, which
will depend on the kind of cement used, the water-colour can be
removed with a damp brush, and the cover can be carefully
cleaned with a piece of soft rag.

If the object, however, is too small to be readily recognised
without a high power, as, of course, is usually the case, for
it is not necessary to mark anything but minute objects,
a rather more complicated variety of the same plan should
be adopted. Again first find the object with a suitable
power, such as a | inch or ^th inch, and let the specimen be as

312 J. BURTON ON A METHOD OF MARKING A GIVEN OBJECT.

accurately placed in the centre of the field as possible ; then sub-
stitute for this power, preferably a water- immersion objective,
say T V^h, put on the front lens a small drop of water and care-
fully focus. It is necessary that the slide should not be moved
after contact is made, as it is desirable to keep the drop of water
as small as possible. When the object is recognised and is in the
centre of the field, raise the microscope tube rather sharply and a
small circular spot of water will be left on the cover-glass right
over the desired place. Now stain this spot with water-colour as
in the other case 1 always use the carmine kept for feeding
infusoria, etc., but any colour will do. When this is dry the
slide may be roughly examined and the object will be seen
through the coat of colour, which for this purpose should not be
too thick. If it be rightly placed, proceed as before, putting a
fine ring of suitable size round the spot with some dark cement,
and when this is dry carefully clean off the colour, and the
arrangement is complete. Water-immersion lenses are not very
commonly used now, and if the microscopist does not happen to
possess one, an oil-immersion may be used instead, but obviously
it must be used with water, not oil ; but this will give a sufficiently
good image for our purpose, which is merely to recognise the
specimen for marking, not to examine it. If an oil-immersion be
not available, any close- working objective, say gth inch or even
-g-th inch may be used, but it is necessary that the front lens be a
small one, so that the spot of water placed by it should be as
local as possible.

There are, of course, some difficulties ; the chief is, that objects
mounted in glycerine as mine usually are are somewhat
liable to move if at all roughly handled, and may work
out of the circle ; but with balsam or glycerine jelly mounts, or
even a shallow glycerine one, there is little danger of this. If a
turn-table is not in the outfit of the experimenter, a sufficiently
good circle may be drawn by hand, or a line drawn to indicate
the position, or, as has been suggested, the barrel of a mapping
pen or similar object may be used. But the first great difficulty
is always to indicate the exact spot it is desired to mark, particu-
larly if the object is a very minute one, and that is got over with
facility by the method indicated.

M. DRAPER, A LIVE BOX FOR THE OBSERVATION OF INSECTS. 313

A LIVE BOX FOR THE OBSERVATION OF INSECTS

AND SIMILAR OBJECTS.

By B. M. Draper.

{Read December 23rd, 1 ( J13.)

This live box, which was worked out for me by Mr. Angus,
displays satisfactorily, with superstage illumination, under the
lowest powers, large creatures such as house-flies. It is not
meant for pond-life.

It is of the simplest description, being really nothing but a
transparent chamber of the shape and size of a small pill-box.
The body is made of a short piecs of glass tube of any size de-
sired, say, one-third of an inch deep by two-thirds in diameter ;
this is cemented to a 3 X 1-inch slip. The lid, which is loose,
is a circular plate of glass of rather larger diameter than the
body. In the lid, near its circumference, and at equal distances
from each other, are fixed three short pins, projecting downwards,
so as to clasp the outside of the body and thus keep the lid in
position. The little collars by which the pins are fixed in the
lid rest on the rim of the box, so as to prevent the lid itself
from touching. The crack thus left gives enough ventilation.
The depth of the box can be varied by means of a false bottom,
preferably opaque.

This box serves well for the exhibition of a fly in the act of
feeding. If a little syrup is put on the inside of the lid of the
box, the sucking surface of the proboscis may be seen in action.

DARK-GROUND ILLUMINATION WITH THE GREEN-
HOUGH BINOCULAR.

By B. M. Draper.

{Bead December 23rd, 1913.)

The Greenhough pattern of binocular consists, as is well known,
of two separate microscopes, one for each eye, with paired
objectives of very low power. Like other binoculars, it is
particularly well suited for use with dark-ground illumination,
and a good way of getting the dark ground with its higher
powers is to put a stop behind the condenser.

314 B. M. DRAPER ON THE GREENHOUGH BINOCULAR.

As, however, the front lenses of the twin objectives stand out
some distance on either side of what would be the optic axis of an
ordinary microscope, the stop has to be correspondingly broad
from side to side ; otherwise direct rays would enter the objectives
and would spoil the dark ground at the sides of the field. But it
is not necessary that the rectangular diameters of the stop should
be equally great ; on the contrary, if an ordinary circular stop be
used, some rays are needlessly obstructed. On trial, a double
or twin stop, corresponding with the twin objectives, gave much
better results. This stop consists of two small circular patches
placed side by side in the same plane, and touching each other r
so as to form a figure of eight. It is used behind the condenser
in the same way as an ordinary circular stop, and with almost
equal ease. It is only necessary to be careful that the two circular
jDatches shall be placed horizontally, i.e. so as to be opposite the
two front lenses of the twin objectives. This position can easily
be secured by arranging the stop in the carrier approximately and
then, whilst watching the object, shifting the whole condenser
round in its sleeve until the best effect is obtained. A standard
low-power condenser such as Swift's " Paragon," with its top lens
off, gives very satisfactory results. The twin and the ordinary
circular patterns of stop were compared experimentally by using a
condenser fitted with two stop carriers, one behind the other, so
that either stop could be used separately, or both together. The
twin stop used by itself gave a good dark ground. The circular
stop was purposely chosen too small to give a good dark ground ;
there was light at the sides of the field. Nevertheless when the
circular stop was turned in above the twin stop whilst the object
was under observation, there was a marked drop in the brightness
of the image. This loss of light was due almost entirely to the
circular stop, not to the clear white glass on which it was mounted,
since it was found that the interposition of such a. piece of glass,,
even when rather dirty, made very little difference to the light.
Evidently, therefore, the circular stop, though too small in one
direction, was too large in the other, and kept out some rays
which might safely have been admitted. Of course if the circular
stop had been large enough to darken the background when
used by itself, the loss of light would have been still more
noticeable.

E. M. NELSON ON AMPHIPLEURA LINDHEIMERI. 315

AMPHIPLEURA LINDHEIMERI.

By Edward M. Nelson, F.R.M.S.

(itearf December 23rd, 1913.)

Half a century ago Xavicula rhomboides was the accredited test
for the best microscope lenses. This was the common " English "
rhomboides, which has about 72,000 to 73,000 striae per inch ; it
was also known as the Amician test. About the seventies
iV. rhomboides was discovered in America. This was a coarser
form, having some 60,000 striae per inch, consequently any 90
| inch N.A. 0*71 would resolve it readily. In those days there
were no cheap apertometers to be had, so testing an objective
merely meant a measurement of aperture by resolving striae
on some diatom by means of oblique light in one azimuth. We
now know that the feat can be accomplished by a very badly
corrected objective.

The new coarse American rhomboides became very popular, and
diatom dotters and brassey glassites simply revelled in it.

History has, however, repeated itself, for as time went on lenses
improved, and both the coarse and fine rhomboides failed as tests
for high powers, so others had to be found to fill their place.
Amphipleura pellucida became the test for immersions, while
A. Lindheimeri was used for dry lenses. As A. Lindheimeri has
about 7 ",000 striae per inch, it is a very suitable test, with oblique
light from a dry condenser, for lenses of the 7a type.

This w T as the favourite test of the late Lewis Wright, who
mentions it in his excellent book on the Microscope. But now
another Lindheimeri has been discovered in Spain, and as it is a
coarser variety, it is necessary to distinguish between these forms
when quoting the Lindheimeri as a test. The new Lindheimeri
has 67,000 striae per inch, and therefoi e is easier to resolve than
the old English rhomboides ; a | inch, or 8 mm., will very nearly
resolve it in fact, they do so in patches; a Powell 100 | inch
of 1S75, which would fail on an English rhomboides, resolves it
easily.

The new Lindheimeri can be recognised at once by its very long
terminal nodules, the terminal nodule being one-third of the whole
length of the valve, while in the old form it is only one-fifth.

316 E. M. NELSON ON AMPHIPLEURA LINDHEIMERI.

The length-breadth ratio in the new form is 7*5, and in the
old 8-5.

The conditions here are therefore opposite to those we found in
Naviada rhomboides,* for those with the greater ratio had the
coarser striae, but in this case they have the finer.

If we divide the ratio by the number of striae in T ff ^th of an
inch we shall obtain a numerical index of about 1*1. Thus :

Old Lindheimeri : Ratio 8*5, striae 7*7, index l'l.

New Lindheimeri : Ratio 7 '5, striae 6*7, index l'l 2.

Amphipleura pellmida follows much the same rule,for "resolvers"
who understood the subject sought out wide valves, i.e. those with
a small ratio.

* Journal Q.M.C., vol. xi. p. 97, 1910.

Jovrn. Qv.ekclt Microscopical Club, Ser. 2, Vol. XII., No. 74, April 11)14

317

SOME NOTES ON THE STRUCTURE OF DIATOMS.

By N. E. Brown, A.L.S.
(Read March 2ith, 1914.)

Plate 23.

These notes are offered to the Quekett Microscopical Club, not
-with the anticipation that, with the exception of one point, the
-expert will find in them much that is not already known, but
because my interpretation of certain familiar features is different
from that which is usually accepted and may therefore be of
some interest in promoting thought in another direction.

Structure of Pirmuiaria spp. Although P. major and allied
species are familiar to all microscopists and their structure is
doubtless well understood by experts, yet the description of it in
English text-books is by no means satisfactory and also does not
seem to be too well known. A good description with figures by
Floegel will, however, be found in the Journal of the Royal Micro-
scopical Society, 1884, vol. 4, p. 509, t. 8 (Pinnularia).

I regard P. major as a very simple type, perhaps one of the
simplest types of diatom-structure. In front view the valve pre-
sents a series of transverse markings on each side of the raphe,
which are so easily seen that I believe few diatom- dotters pay much
attention to them. These markings consist of linear cavities or
canals in the valve, separated from one another by very thin par-
titions, and each of them is provided with a comparatively large
linear-oblong opening on the inner side, communicating with the
interior of the diatom ; it is evident that during life the protoplasm
enters and fills these cavities, and therefore they must play an
important part in the life-economy of the diatom. The motions of
n living diatom are not only interesting to watch, but are puzzling
to everv one who has observed them. It is no uncommon thing to
see a Pinnularia or other free-swimming diatom apparently take
hold of a particle of dirt and move it to and fro along its sides or
upper surface. On one occasion I saw P. major with two frag-
ments of dirt, one on each side of it near the margin ; both pieces
"were moved forwards and backwards in the same direction for
-a time and then suddenly they were moved each in a different

318 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

direction, and finally one piece was passed from one side completely
round one end to the other side, where, upon meeting the other
piece of dirt which was moved towards it, the invisible hands
moving the dirt lifted it up and placed it upon the other piece of
dirt and held it there, both together being then moved up and
down as before. Now this and other movements I have witnessed
could only have been made at the will of the diatom, and in my
opinion must have been controlled by living matter extruded from
the interior of the shell, and therefore there must be openings
through which the interior is in communication with the exterior
other than at the raphe, where, as is well known, a crest of proto-
plasm extrudes, which, from measurements I have made, varies
from l/14,000th to l/3,000th inch in depth and l/6,000th to
1/1. 800th inch in breadth. Feeling convinced of this, I sought
for several years for evidence of pores in Pinnularia without
finding the slightest trace of them, and all authors I have con-
sulted state that there are no openings in the valve of Pinnularia
other than at the raphe. With respect to diatoms in general,,
in the 8th edition of The Microscope and its Revelations (1901),
p. 590, it is stated, " We have in fact no positive demonstration
of the existence of special apertures communicating between the
outside and inside of the cell."

However, some four years ago I obtained a sample of the
Chei-ryfield diatomaceous deposit, and upon mounting some of it
in picric piperine, found that it contained four or five species of
Pinnularia, on one of which I at last saw indications of the pores.
I had so long sought. This species is one of the smallest in the
material and the only one on which I have been able to see any
indication of pores. They are only to be seen when the outer
surface of the cavities is accurately in focus and the light central,
and are so minute and crowded that they appear like a single
dusky beaded line extending all the way along the centre of the
cavity, and they do not appear to be present at any other part. At
any focal plane below the external surface, such as when the large
opening into the interior of the diatom is in view, they cannot be
seen. When viewed from the inside of the valve they are scarcely
visible except where seen through the large opening of the cavity
into the interior. Although a distinct bead-like appearance is just
discernible, the pores are so closely placed that neither I nor the-
friends to whom I have shown them, have been able to see them

N. E. BROWN ON THE STRUCTURE OF DIATOMS. 319

as distinctly separate dots. It is only on this particular species,
the name of which I do not know, that I have been able to discern
these pores. Upon the far larger P. major and P. nobilis I can-
not see any trace of them, although I do not doubt that they
exist in these species also, but are probably smaller than in the
species in which I discovered them. As seen by myself and
friends at a magnification of 3, COO diameters they are as repre-
sented at PI. 23, fig. 13.

Upon the sides or girdle of all species of Pinnularia are to be
seen two slender lines, which under sufficient magnification are
seen to be composed of a multitude of short transverse lines ; in
P. major these average about 60,000 to the inch. These lines I
have failed to resolve into distinct dots, although Mr. E. M.
Nelson (Journ. Q.M.C., Ser. 2, Vol. VI. p. 144) states that he
has done so, and I do not doubt his statement. But at the same
time I very much doubt if the clots of which these transverse
lines are composed are real pores. The lines are so easily seen
that they evidently are much too coarse for pore structure, and
my interpretation of the structure of these two lines on the
girdle of Pinnularia is, that each line consists of a multitude
of very minute cavities placed side by side, similar to those seen
in the front view of the valve, and that when they are truly
resolved each cavity will be found to have a minute pore at the
centre or a row of pores along the central line of each cavity or
clear space between every pair of short transverse lines.

It may be well to state that there are sometimes appearances
to be seen on the walls of the cavities of P. major and P. ?iobilis
which may easily be mistaken for rows of pores. As I have
seen them, they appear like two rows along each cavity, but
upon moving the mirror slightly these rows move also, and
clearly demonstrate that they are only diffraction images.
The true pores of these species, when discovered, will, I believe,
be in one central row.

Pleurosigma balticuni. In a paper recently published in the
Journ. Q.M. 6'., Ser. 2, Vol. XII. p. 155, Mr. T. O'Donohoe has given
an account, accompanied by some excellent photographs, of certain
details of structure of this diatom as seen in a strewn slide
mounted in realgar belonging to Mr. B. J. Capell. By the
courtesy and kindness of Mr. Capell I have also had the privilege
of examining this slide, and am fortunate enough to be able to

320 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

add something concerning the structure to be seen on it that
appears to have escaped the eyes of Mr. O'Donohoe.

In the process of melting the realgar, either the great heat
required, or some chemical action set up by it, has acted upon
some specimens of P. balticum and completely dissolved part
of the shell, leaving only film-like strips flattened upon the
cover-glass, whilst others have been quite unaffected. One
specimen shows in a very clear manner the dissolving action in
progress, but arrested at the moment when a subcentral part
of the diatom had become fused into a structureless strand of
silica, connecting the two ends, which remain intact. These
films above mentioned, which Mr. O'Donohoe has photographed,
will prove, I think, to have an important bearing upon our
more complete understanding of diatom structure.

If the outer surface of a perfect valve of P. balticum be
examined under a binocular, it will be seen that the sides curve
away from the raphe very much as the sides curve away from
the keel of a boat when turned bottom upwards, so that the
surface is nearly always oblique to the surface of the cover-
glass. From this cause I have found the structure of a perfect
specimen extremely difficult to understand, as a very slight
modification of the illumination or alteration of focus under high
powers, or the two combined, produce a number of different
appearances six or seven have been noticed all apparently
demonstrating true structure, so that it is practically impossible
to form an opinion as to which view, or views, represent the real
structure of the valve. Owing to this, I suppose, has arisen the
diverse views held of the structure by different authors. 0. Miiller,
for instance, in" the Deutschen Botanischen Gesellschaft for 1898,
Vol. XVI. p. 387, t. 26, fig. 8, regards the pores (by which
I understand he means the black dots) in the cell- wall as
perforations passing completely through the wall, which are
not perfectly tubular, but enlarged at their centre and contracted
to a minute opening on the internal and external surface of the
valve thus :

porej

Mr. T. F. Smith, however, in the Journ. Q. M. C, Ser. 2,

N. E. BROWN ON THE STRUCTURE OF DIATOMS. 321

Vol. III. p. 306, regards the valve as "composed of two layers
of grating"; whilst Mr. E. M. Nelson in the Journ. Q.M.C.,
Ser. 2, Vol. XII. p. 99, fig. 4, states that " in P. balticum
and allied forms the upper membrane has slit-like apertures in
longitudinal rows, while the lower membrane has circular
apertures (fig. 4), where the circular apertures in the lower
membrane are seen through the intercostal silex of the upper
membrane and in a line between the slits." Finally we have
Mr. O'Donohoe's interpretation referred to above.

Until August 1913 I held the view (which I think is the
prevailing one) that the black dots visible on the valve of a
diatom were pores or perforations passing completely through
its substance, and that the white-dot view was an out-of-focus
one. Now, however, the examination of Mr. Capell's slide has
demonstrated to me and to others who have examined it with
me, conclusively and beyond any room for doubt, that many
(possibly all) of the black dots that are ordinarily seen on a-
diatom are not pores at all, or at the most are only pits con-
taining the pore-bearing membrane, and that the white-dot view
is often much more correct for seeing what I believe to be the
true pore-structure than has been supposed.

I have long been puzzled at the behaviour of black dots under
high magnification, and have therefore suspected that they
were not quite what they seemed to be for some time past, but
I think the evidence of Mr. Capell's slide fully explains their
nature.

In any perfect valve of P. balticum it is easy to obtain a view
of a grating-like structure with square meshes, formed of bars-
or rods of silex crossing one another at right angles. In the
partly dissolved films on Mr. Capell's slide this grating is not
evident, but instead the films are seen to consist of parallel
dark rods having a beaded appearance, held in place by a
membrane of silex (see Mr. O'Donohoe's figures, op. cit., t. 14 r
figs. 3 and 4). At the ends or other parts the rods are seen
to project in a ragged manner. These rods are those which lie
parallel to the raphe in the perfect grating, while those which
in the perfect diatom form the transverse bars of the grating
structure have been dissolved, leaving no trace, or only a very
faint one, visible. When examined with an oil-immersion objective
at a magnification of 2,000 to 3,000 diameters these bars are

322 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

seen to be thickened in a beaded manner at short equal intervals.
Tn some cases a few of these rods are curved away from the
surface of the valve, and one of them in such manner that part
is seen in surface view and part seen in side view, and traceable
from one view to the other (see Mr. O'Donohoe's photograph,
op. cit., t. 14, fig. 2. where it or a similar rod is shown out of
focus). Now it is obvious that the bead-like swellings occur at
the points where, in the perfect grating, the transverse bars
crossed and were fused with those parallel to the raphe, and
that these transverse bars were either more easily dissolved or
lie at a slightly lower level than the longitudinal bars, and so
are more quickly attacked by the dissolving action. In all cases
the films are very closely appliel to the cover-glass, indicating
that its cooler surface has in some way retarded the dissolving
process, so that the parts of the diatom farthest from the cover -
glass were always dissolved first. That the longitudinal bars over-
lie the transverse bars seems to be probably the correct view, as
under certain conditions of illumination the longitudinal bars seem
to pass over the transverse ones, and is supported by the testimony
of the curved bar mentioned above as seen in side view. At
a magnification of 3,000 diameters it is clearly seen that the
edge of the bar facing the outside of the diatom is perfectly
even, while the edge facing the interior projects into little hemi-
spheres at the points where (in surface view) it is bead-like (fig. 2).
Also at the marginal part of the valve, where the longitudinal
bars are normally undeveloped and only the transverse bars
are evident, these latter become pressed nearer to the cover-
glass, and are not dissolved.

The bars can be distinctly seen to be solid pieces of silex, which
go to form the strengthening grating and support the membrane
which covers the exterior of the diatom. At a certain focus the
beads or nodes at the crossing of the bars, owin2f to refraction
or diffraction, assume the appearance of black dots so familiar to
all microscopists, demonstrating conclusively that these black
dots are not pores, but shadows produced by some refractive
or diffractive property of the nodes of the grating-bars.

From the movements T have seen diatoms perform it is evident
they must have some means of communication through the valves
with their surroundings, and finding that the black dots on this
diatom are certainly not pores, I sought for them in the membrane

X. E. BROWN OX THE STRUCTURE OF DIATOMS. 323

covering the meshes of the grating. This membrane is extremely-
thin, probably not thicker than the film of a soap-bubble, and
is raised into a slight dome or convexity over each mesh of the
grating. When the apex of these convexities is accurately in
focus, and the headings of the bars seen as black dots forming
squares, the light being central and with a magnification of
2,000 to 3,000 diameters, a very minute dot is seen at the
centre of each square (PI. 2, fig. 1). This central spot I conceive
to be a true pore through the membrane ; it is very minute, at
the most not more than one-third of the diameter of the black
dots themselves, and is probably not more than 1/200, 000th of an
inch in diameter. It is not quite easy to see, but can be made
clearer by the use of a small central stop in the substage con-
denser. I doubt if it can be seen at all at a less magnification
than 1,000 diameters; and with a dry Zeiss y-th, at a magnification
of 3,000 diameters, I do not feel quite sure that I see the pores.
There seems a suggestion of their presence, but I do not think
any dry lens will show them very clearly. Under dark-ground
illumination, with a Leitz dark-ground illuminator, the bars
are white and the headings on them appear much larger than
when seen by direct light, whilst the membrane is not seen at
all, the spaces between the bars being black. But if the funnel-
stop which cuts down the aperture of the lens is removed, the
illumination remaining as before, then the bars appear to be
very slender and black and the membrane whitish, with the
minute pores clear and distinct.

Upon entire specimens of the diatom the pores are difficult to
see, apparently owing to the convex curvature of the shell, but
with a little trouble I have been able to see them in places upon
every specimen examined. Under certain conditions of illumina-
tion a small dark spot, which might easily be mistaken for the
pore, is seen at the centre of each of the beads of the membrane ;
this spot, however, is very much larger than the true pore,
and appears to be some diffraction image, possibly that of the stop
in the condenser, as can easily be demonstrated by moving the
mirror slightly, when the spot is seen to shift its position.

Although all to whom I have shown these pores agree with me
that they are very minute, yet they appear to have a different
size to different observers. To my eye they appear to have about
the proportion to the black dots I have represented in my drawing,

Journ. Q. M. C, Series II. No. 74. 23

324 N. E. BROWN ON THE STRUCTURE OF DIATOMS. N

to others the} 7 evidently seem larger, as one friend said he thought
that about five of them just touching one another would extend
right across one of the meshes of P. balticum, but even at that
rate they would not be more than 1/1 80,000th of an inch in dia-
meter, whilst I think they cannot be more than l/200,000th
of an inch in size.

With regard to Mr. Smith's statement that there is a second
grating, I have not the slightest doubt that the transverse bars
form such a grating, but I have not seen it separately from the
outer grating. In Knowledge for 1911, p. 334, Mr. Smith
reproduces a photograph of P. balticum in which the longi-
tudinal strengthening bars are shown and are there called
" fibrils," a term which Mr. O'Donohoe has also adopted, but
which to me seems wholly inapplicable, as they appear to me to be
supporting structures for the delicate membrane and in no sense
ultimate structures. It may not be out of place here to point
out that the membrane I speak of and illustrate is a totally
different thing from that which Mr. Smith in the Joum. Q. M. 0. f
Ser. 2, vol. 3, p. 301, t. 3, fig. 5, and in Knowledge (1911), pp. 289-
93, and 221-35, and (1912) p. 371 describes and figures as a
"delicate membrane' 3 and "torn structure." For it is a
matter of great surprise to me that Mr. Smith did not recognise
that this supposed "delicate membrane " and "torn structure"
has no morphological connection with the diatom. I had sup-
posed, previous to reading his paper, that every one regarded
this appearance merely as an incrustation cementing the diatom
to the cover-glass ; it is of very common occurrence upon
Pleurosigma and some other diatoms. I have always regarded
it as due to the exudation of a residual salt, which, after
boiling in acid, has not been thoroughly washed out of the diatom
(and it is indeed very difficult to wash out completely), so that
when mounting them on a cover-glass the water outside the
diatom evaporates first and the salt then gradually percolates out
through the pores of the diatom, and, in drying, fixes it to the
cover-glass, and being of low refractive index produces the
appearance we so often see.

It will be noted that there is a discrepancy between my
drawings and Mr. O'Donohoe's photographs in the size of the
black dots, for although mine are represented at a greater
magnification, they are smaJler than in the photograph. This is.

X. E. BROWN ON THE STRUCTURE OF DIATOMS. 325

probably because the photographs were taken at a focus where
the membrane is not visible and where diffraction effects are at a
maximum, whilst at the focus of the surface of the membrane
they are reduced to a minimum.

Since writing the above I have had the advantage of being able
to examine a realgar mount of P. balticum belonging to Mr. E.
M. Nelson. The realgar of this slide is not nearly so clear and
brilliant as that of Mr. CapelTs slide, and on some parts of it I
cannot see the pores in the films at all, but there are some films
where they can be most distinctly seen. I mention this, because
others possessing realgar mounts of this diatom might fail to find
the pores on some of the films and believe them not to be present ;
they may be extremely difficult to make out, or quite invisible on
parts of the valve where both longitudinal and transverse grating
or strengthening bars are present.

Pleurosigma angulatum. Upon Mr. Oapell's realgar slide
are also numerous specimens of this diatom ; some are bent or
contorted, but otherwise, with the exception of two or three
specimens, seem unaffected by the heat or dissolving action.
One of these exceptions, however, is an exceedingly interesting
specimen, and clearly confirms Mr. E. M. Nelson's statement in
the Journ. Q. M. C, Ser. 2, Vol. XII. pp. 98-100, that the valve
of this diatom is composed of two gratings. It is a single valve
and therefore its structure is not obscured by images from the
opposing valve, is fractured in places, and has its outer surface
next the cover-glass, as can be verified by examination under a
binocular. Over a small area some solvent has caused a portion
of the outer grating to peel off, and at one place a small patch of
it is seen adhering to the cover-glass ; this patch is represented at
fig. 5, as seen when magnified 3,000 diameters. At this magnifi-
cation the bars of silex forming the boundaries of the meshes are
seen to cross one another diagonally, forming diamond-shaped
meshes, and are thickened at the nodes or points of intersection
just as in P. balticum, and, as in that diatom, it is these nodes
which produce the black-dot appearance. At the centre of
the membrane covering each mesh a very minute pore can be
seen when the surface of the membrane is accurately in focus.
These pores do not seem to be visible under direct central light
without the interposition of a stop in the condenser, and I find
that they are best seen when illuminated by means of a Leitz

326 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

dark-ground illuminator, but without using a funnel-stop in the
lens. Under this method of illumination they are remarkably
clear and distinct, and the membrane itself appears to be slightly
concave as viewed from the outside of the valve. At one focus
and under slightly oblique illumination, one set of bars appears to
cross over the other set, as I have represented diagrammatically at
fig. 6 ; at this focus the pores are invisible. Upon the specimen
from which the fragment is separated both the outer and inner
gratings are seen to be composed of hexagonal meshes, as at
figs. 7 and 8, and I find it very difficult to get a view of the
diamond-shaped meshes on the entire part of this particular
specimen, although upon other specimens I have been able to see
them and the pores very clearly and easily, as well as the under-
lying hexagonal meshes. It would seem as if the outer grating
may really be a double structure, with a film of diamond-shaped
meshes overlying others that are hexagonal.

Under certain conditions of illumination a third set of bars can
be seen on entire specimens, crossing the diagonals at right angles
to the raphe, but I have failed to see any trace of them on the
separated fragment represented at fig. 5, so that I think it very
probable that they have been dissolved away from that piece,
just as also appears to have been the case in the films of
P. balticum. For I think there can be no doubt that some such
bars exist, because at one focus, under varying conditions of
illumination, the gratings appear to be composed of nearly square
meshes as represented at fig. 9. At a very slight alteration of
focus this appearance alters to the hexagonal one as represented at
figs. 7 and 8, which I take to be that of the exact focal plane of
the membrane covering the meshes of that particular grating.
When the inner grating is examined where the outer grating is
stripped off, looking upon it from the outside of the valve, it first
presents the appearance of a solid plate of white silex with dark
hexagonal perforations in it. At a slightly lower focus this gives
place to hexagonal meshes with dark boundaries and the mesh
covered with a clear membrane having a pore at its centre ; this
latter I look upon as being the true image of the inner grating
and the above-mentioned appearance of a white plate with dark
perforations as an out-of-focus image produced by some refractive
or diffractive property of the membrane, which in some way
produces over each mesh a hexagonal shadow. Below the focus

N. E. BROWN ON THE STRUCTURE OF DIATOMS. 327

of the hexagonal meshes I can sometimes make out a diamond-
shaped arrangement of dark dots as seen in fig. 5.*

In this species, as in P. balticum, wherever a junction of two
or more bars of a grating occurs, there a black dot is seen, due to
diffraction or refraction of the node so formed. And in my
opinion wherever grating structure occurs, the nodes may be
expected to appear as black dots.

At one place a fragment of the valve is broken off and turned
edgeways to the cover-glass. This edge-view shows the two
gratings distinctly, but at the same time, owing to the shadow of
the mass, I am quite unable to see how they are connected to each
other. But from an examination of this piece, as well as of the
valve where the outer grating is stripped off, it is evident that
the faint brown colour peculiar to this diatom resides in the outer
grating, the inner one being colourless.

I cannot, however, confirm Mr. Nelson's statement (Journ.
Q. M. C, Ser. 2, Vol. XII. p. 99) that the meshes of the outer
and inner grating alternate with one another, for in this particu-
lar specimen I think there can be no question that the meshes of
the outer grating are exactly superposed over those of the inner
grating when seen with exactly central light. I have tested them
several times by the unaided eye and by means of a micrometer
in the eye-piece, and always found them to correspond, except
when the light was not absolutely central. Also the edge- view
confirms their superposition so far as I have been able to make it
out, but it is very difficult to get a really good focal image of this
part.

P. angulation has one very obvious peculiarity which I do not
remember to have seen mentioned, namely, that at the ends of the
valve the grating suddenly changes from the hexagonal to the
square type of mesh. This should form a good specific character.

Surirella gemma. Mixed with Phurosigma balticum on Mr.
Capell's slide are numerous specimens of Surirella gemma, which,

* Mr. T. F. Smith is of opinion that the outer grating is different in
structure from the inner grating, and views of both gratings are given in
The, Microscope and its Revelations, 8th ed. p. 593, pi. 1, figs. 1 and 2. I
am not able to confirm this view, for every structural image seen on the
outer grating I have also"been able to see on the inner grating it is merely
a question of focus and illumination. The "delicate membrane" on the
outside of the shell described by Mr. Smith I have already noted under
P. balticum, so need not make any further remark upon it.

328 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

in consequence of having seen the minute pores in P. balticum, I
eagerly examined, as I was reminded that some four years ago
whilst examining S. gemma mounted in styrax with a Leitz
-jL.th achromatic oil-immersion objective of 1*3 N.A. I had seen
similar pores or dots on the white beads of that diatom. At the
time, being very busy with other work and thoroughly accepting
the opinion that the black dots usually seen were pores, I paid no
attention to what I then saw. Now, however, I examined them
with fresh interest and found that in this realgar mount the pores
are distinctly visible. To see them, the valve must be resolved
into a grating formed of slender, slightly zigzag black bars, with
the interspaces divided by very slender transverse partitions into
small meshes (the so-called white-dot focus). At a magnification
of from 1,800 to 3,000 diameters on some specimens, but not all, a
minute dark speck or pore at the centre of every one of the
meshes is very clearly visible (figs. 3 and 4) ; at the same time
it is so minute that it requires good eyesight to perceive it,
but, as in other cases, becomes accentuated if a small stop be
placed in the carrier of the condenser. There is therefore no very
great difference in the ultimate structure of this Surirella and of
Pleurosigma balticum, except that in the latter it is the bars
parallel to the longer axis of the diatom which are most evident,
whilst in Surirella gemma the bars transverse to that axis are the
most apparent. It must be understood that I refer here only to
the fine secondary bars or those of the cell-wall, not to the stout
primary bars which form the framework of the diatom and sup-
port the cell- wall. The nodes, formed by the junction of the
slender partitions with the bars, at another focus produce the ap-
pearance of black dots by refraction or diffraction as they do in
Pleurosigma balticum. One specimen of S. gemma on the slide is
crumpled up and the bars bent and turned aside so as to show
their nature very clearly when sufficiently magnified, and demon-
strate that they are exactly of the same character as those of
Pleurosigma balticum that is, they are the strengthening bars of
the membrane of the diatom. I have been unable to determine
whether there is also a membrane over the inner surface of these
bars, but think it very probable, in which case the white bead-
like appearance will be chambers with minute orifices in their
iuner and outer wall.

This diatom seems to provide the microscopist with a series of

N. E. BROWN ON THE STRUCTURE OF DIATOMS. 329

tests ; with lenses having a smaller aperture than about 68 N. A.
only the primary bars of the framework are visible ; with lenses
of a larger aperture, the secondary bars (i.e. those of the cell- wall)
become manifest as very fine lines between the primary bars;
finally with lenses of large aperture and at a magnification of not
less than 1,800 diameters these fine lines or bars are seen to b9
connected by finer transverse bars so as to form a ladder-like
structure, with a minute pore at the centre of each bead-like
space formed by the cross bars, or at another focus the bars can
be resolved into the appearance of rows of dots.

Navicula serians. The structure of the valve of this species
seems rather difficult to understand. When I first examined it
in search of pores, I found it had a rather coarse grating, with
oblong meshes arranged in six to seven rows on each side of the
raphe, the longer diameter of the meshes being transverse to the
latter. These meshes are closed by a very thin membrane of
silex, at the centre of which can be seen, at a magnification of
3,000 diameters, a minute dark dot, as represented at the upper
part of fig. 10. This clot I take to be a pore. With central
light only a very faint indication of it is seen ; but when a small
central stop is placed in the condenser it becomes clearly visible.
This structure is all that I at first noted. But having re-
examined this diatom with great care under all conditions of
illumination at my command, I have detected structure which had
previously entirely escaped my notica. For I find that if the
outer surface of the valve is illuminated by a Leitz dark-ground
illuminator and examined at a magnification of not less than
2,000 diameters, without reducing the N.A. by using a funnel-
stop, a second grating exterior to and superposed ^upon that
above described can be distinctly seen. This outer grating is
evidently extremely transparent and practically invisible by
central light, so that it very easily escapes notice. I have found
that the easiest way to make it evident is, first to get [the mem-
brane of the coarse meshes in focus, as represented at the upper
part of fig. 10, then gradually but very slightly raise the lens
above that focal plane, until two dark dots appear over each
mesh. If these dots are very accurately focused and the dark-
ground illuminator manipulated so as to illuminate the diatom
with light reflected upon it from the under surface of the cover-
glass, the surface of the valve will be found to have the 'appear-

330 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

ance I have tried to represent at the lower part of fig. 10. I
believe that each of these dots, or minute meshes as they really
are, is closed by an extremely thin membrane of silex, as on one
occasion, when using a dim light reflected from the cover-glass
upon the diatom, the presence of such a membrane seemed to be
very distinctly evident by the light reflected from its surface over
each dark spot and nowhere else. But I entirely failed to see
the slightest trace of a pore in it, although I think it probable
that one exists in each mesh.

Nitzschia scalaris. When the fine striae on this diatom are
magnified up to 3,000 diameters, they are seen to consist of
small beads or pearl-like dots of silex, which are either black or
white according to illumination. Upon the very thin membrane
between each pair of these rows of beads, a row of very minute
pores is just discernible, as represented at fig. 11, which is
drawn with a camera-lucida, using central light and a green
screen. Under the best of circumstances they are exceedingly
faint, and I am not at all sure that they are accurately spaced
in my drawing, as I found it exceedingly difficult to plot them on
paper by means of a camera-lucida ; but the drawing is suffi-
ciently accurate to show their position. It requires good eyesight
to see them at all, and I do not think they would be visible at a
less magnification than 2,500 diameters. The light must be
most carefully manipulated, and for my vision I have found
them to be most evident in a rather dim light, a glare effaces
them ; also at a very slight touch of the fine adjustment they
instantly vanish. As a test for high powers, manipulative skill
and keenness of vision, I think few things can be found more
suitable than the resolution of the pores of this diatom when
mounted in styrax.

Amphipleura Lindheimeri. When the surface of this
diatom is accurately in focus (not the black-dot view), a fine
grating with square meshes is seen, which somewhat resembles
that of Surirella gemma ; the bars transverse to the raphe being
straight, whilst those parallel to the raphe form sinuous lines,
because the ends of the short partitions which divide the space
between each pair of transverse bars into square meshes do not
exactly coincide with the ends of the partitions between the
adjoining pairs of transverse bars. At a magnification of 3,000
diameters, when the membrane covering the meshes of the

N. E. BROWN ON THE STRUCTURE OF DIATOMS. 331

grating shows a somewhat bead-like appearance, a very minute
dusky dot, which I take to be a pore, is just discernible in the
centre of every one of them, as represented in fig. 12. These
pores, I think, are smaller even than those of Sarirella gemma,
and are very difficult to see, unless perhaps to younger eyes, as
I judge them to be about the limit of my vision. At a slightly
lower focus the nodes formed by the junctions of the transverse
and longitudinal bars assume the well-known black-dot appear-
ance, and all trace of the other structure disappears. Doubtless
the structure of A. pellucida is similar.

Coscinodiscus heliozoides. I have nothing to remark
upon the structure of the diatom to which Mr. Siddall recently
gave the above name; but I should like to call the attention of
experts to its remarkable similarity to Stepkanodiscus Hantz-
schianus. I have not been able to compare the two, but feel
sure that C. heliozoides belongs to the genus Stephanodisats,
and have a suspicion that it and S. Ilantzschianus are one
and the same diatom. A good figure of the latter will be found
in the Deutschen Boianischen GesellscJiaft, 1S97, vol. 15, t. 25,
h> 1

Stauroneis phoenicenteron. When examined at a magni-
fication of a few hundred diameters, the valve of this diatom is
seen to be prettily marked with black dots ; but when magnified
2,000 to 3,000 diameters and very accurately focused, the black
dots are seen to be optical effects produced by the membrane
closing the meshes of the grating. This membrane is slightly
sunk below the general level of the surface of the grating so as
to form shallow pits. When viewed with the light quite central,
without a stop, the bars of the grating appear very much stouter
and the meshes smaller and not so well defined as they do by
other methods of illumination, and I have quite failed to detect
any trace of pores in the membrane by this method. But when
oblique illumination is used, either by means of Powell & Lea-
land's chromatic immersion condenser or by a Leitz dark-ground
illuminator, in such a manner that it is reflected from the under
surface of the cover-glass upon the diatom, then a pore in the
centre of the membrane of each mesh or pit is distinctly per-
ceptible, and the structure has the appearance represented at
fig. 14, which is drawn by means of a camera-lucida from a
portion of the grating adjoining the " stauros," at a magnification

332 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

of 3,000 diameters. The pores are best seen when the light is
not very brilliant.

Triceratium favus. The structure of this diatom, as well
as that of several other species, has been described and illustrated
in a very interesting article by Floegel in the Journal of the
Royal Microscopical Society, 1884, vol. 4, p. 665, t. 9, figs. 21 and
22, and by Otto Miiller in the Deutschen Botanischen Gesellschaft,
1898, vol. 16, p. 387, t, 26, fig. 5, and 1899, vol. 17, p. 435, t. 29,
figs. 1 to 5. Both these authors figure and describe the valve
as consisting of honeycomb-like hexagonal chambers, which are
open at the outer surface and closed by a very thin perforated
plate at the inner surface of the shell. Floegel made sections of
the valve, and from his drawings of what he saw one would
expect his interpretation to be correct. Miiller's interpretation
is substantially the same. I have not made sections, but from
repeated observations of the external appearance of the valve
I am convinced that their interpretation is not correct. If
the outer surface of the shell of T. favus is examined under a
binocular, with a y^th oil-immersion objective, using either oblique
light or oblique light reflected from the under surface of the
cover-glass upon the object (the Leitz dark-ground illuminator,
when decentred, acts admirably for this purpose), a thin plate of
silex closing the external opening is very distinctly evident, for
light-reflections and shadows can be very clearly seen upon it,
and are seen to move over its surface when the mirror is slightly
moved. The appearance is represented in fig. 15, made from a
camera-lucida drawing, in which the outline was made by viewing
it under a monocular, with central light, at a magnification of
1,500 diameters, and the shading put in to show its appearance
as seen under a binocular at the same magnification with oblique
light, the chamber chosen being midway on the slope between the
apex of the convexity of the outer surface of the valve and the
margin. This closing membrane I believe to be very thin, and
probably any section of it that Floegel made would be nearly or
quite invisible, and therefore easily overlooked. I fail to detect
any pores in it, although I have examined it by several methods
of illumination ; but at the same time there is a faint indication
of some kind of fine-grained surface which may ultimately prove
to be pore-structure.

Upon examining the inner surface of the valve at the same

N. E. BROWN ON THE STRUCTURE OF DIATOMS. 333

magnification and with oblique illumination, the appearance of
the closing plate is as shown at fig. 1G, represented for effect as
at black-dot focus, and drawn and shaded by the same method
as fig. 15. If, however, it is examined by dark-ground illumi-
nation, and especially if the illuminator be decentred so as to
reflect the light from the under surface of the cover-glass upon
the diatom, the closing plates appear to be much more raised
than as seen by oblique light and nearly hemispherical ; which,
however, is the correct appearance I am unable to say. Both
forms of illumination distinctly demonstrate that the outer and
inner closing plates have their central part raised above their
marginal attachment, or, in other words, each closing plate is
separated from its neighbours by a furrow. Floegel and Miiller,
however, both represent the inner plate as perfectly flat and
even, and continuous with that of the adjoining chambers, and in
their drawings (which I think must be somewhat diagrammatic)
of considerable relative thickness. Floegel represents the inner
plate as containing small cavities in its substance, closed on all
sides. Miiller, in the figure he published in 1898, represents the
plate as having small perforations through its substance, whilst
in that published in 1899 he represents the plate as having
small concave pits extending half-way through its substance on
the side facing the interior of the diatom. This latter view is,
I believe, much more correct than the other two interpretations,
for I find that at a magnification of 3,000 diameters, when the
light is oblique, or reflected upon it from the inner surface of the
cover-glass, so that the plate is of a dull greyish-white colour,
it is clearly seen to have pit-like cavities in it closed by a
membrane which is probably situated at the other surface of
the plate. These pits can be clearly demonstrated by gently
moving the mirror, when the shadow formed by the wall of the
pit is seen to move round upon the membrane at the bottom of
the pit. The appearance of the pits as seen with the light
reflected upon them from the under surface of the cover-glass at
a magnification of 3,000 diameters, but enlarged to somewhere
about 10,000 diameters, is as represented at fig. 17. This mem-
brane under this form of illumination is white, and is probably
very thin. When viewed with central light and accurately in
focus, it appears more transparent than the thicker plate-
substance, and the light shows through it more brightly. But

334 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

when examined under dark-ground illumination the reverse
sterns the case, for then the plate-substance appears to have
the transparent of a black sky, and the membrane of the pits
reflects the light so as to appear like minute golden stars. It is
by some refractive or diffractive property of this membrane that
the black-dot appearance is produced, for when the membrane
itself is accurately in focus no black dot is seen ; but if the focal
plane of the lens is above the focus of the membrane, then the
black-dot appearance is produced, and appears to me nothing
more than a deceptive light effect. From the different appear-
ances of this membrane under different methods of illumination
and its contrast with that of the plate, I think it must be of a
somewhat different nature. Although I suspect that it is per-
forated, I have quite failed to perceive any trace of pores in it ;
higher magnification than I am able to obtain is probably needed
for demonstrating anything of that nature.

In conclusion, from the evidence afforded by Mr. Capell's slide
and from the observations I have made upon other diatoms not
hastily formed opinions, but based upon many hours' examination
under all forms of illumination it seems clear that we can no
longer regard all the black dots usually seen upon diatoms as
being pores through the shell, although there may be cases
where they are so ; for in the cases examined they are certainly
nothing more than light effects or shadows, either caused by the
nodes of the grating structure, as in Pleurosigma ; or by the
membrane closing the meshes of the grating, as in Stauroneis ;
or by the membrane closing the pits in the cell-wall, as in
Triceratium.

What I take to be the true pores must be sought for in the
thin membrane of silex closing the meshes or pits. If these
are not pores, then I do not know where we are to seek for them.
I think it must be perfectly obvious, to all who like myself have
carefully studied the movements of living diatoms, that there
must be openings or pores through the shell communicating with
the interior. This seems also conclusively proved in cases where
the shell certainly has chambers in its substance, as in Triceratium
favus, Pleurosigma angulatum and others, for in the ordinary
process of mounting the medium penetrates easily into the
interior of the cavities, and they can also be filled by chemical
deposits, which I do not think would be the case if the membranes

N. E. BROWN OX THE STRUCTURE OF DIATOMS. 335

closing these cavities were solid, imperforated films of silex ; no
osmotic theory will account for it.

Also it is quite certain that there is some extrusion of motile
living matter from the interior to the exterior of the diatom,
which is controlUd by the will of the organism.

No one has yet been able to detect any protoplasmic filaments
or pseudopodia (other than the crest of protoplasm along the
raphe) protruding from the pores of diatoms, and if they are as
fine as the pores I have seen would seem to indicate, and as trans-
parent as protoplasm, I doubt if we ever shall see them on the
living diatom, as the nearness of their own refractive index to
that of water would not provide sufficient contrast to enable us
to detect them. Killing and staining do not seem to prove
successful in demonstrating anything of the nature of pseudopodia,
only the crest at the raphe and a very thin layer of protoplasm
sometimes covering the whole shell can be made evident,
so far as I have been able to demonstrate it, but it ought not to
be lost sight of that there is a possibility that a diatom may be
able to speedily retract any protoplasmic matter that it may
protrude from its shell or from the film of protoplasm that some-
times covers its shell, so that at the slightest indication of the pre-
sence of anything injurious, all external protoplasm of the nature
of pseudopodia may be suddenly withdrawn before the diatom is
killed. Usually there is no evidence that any living matter is
protruded to any distinct distance from the shell, except at the
raphe, as any substances taken hold of by a diatom are generally
seen in apparent close contact with the shell, although occasionally
one is seen dragging a niece of dirt along at a short distance
behind it by an invisible thread. But upon a few rare occasions
I have witnessed a diatom seize and move pieces of dirt that were
at an appreciable distance from the shell, and on one occasion
last autumn I was able to measure the interval between the
diatom and the dirt. I was observing a large species of Surirella,
probably S. biseriata, which was moving rather quickly across the
field, when I saw it seize with invisible hands a large piece of dirt
at a little distance from it, and pull it along by its side, without
decreasing the distance between itself and the dirt. I at once put
on an eye-piece with a micrometer scale on it, and carefully noted
the distance separating the dirt and diatom upon the scale, and
then substituted a stage micrometer for the diatom and found that

336 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

the distance to which the pseudopodia (if I may term them so)
extended was between 1/3, 000th and 1/4, 000th of an inch. After
carrying it along across about one-third of the field of view,
it released its hold of the dirt, and in doing so I saw it give a
very slight but distinct jerk, just as if something had snapped
suddenly, for the mass of dirt was very much larger than itself.
This observation was made with a fth lens.

Finally a word as to the pores. It must not be expected that
they can be rendered visible in as easy a manner as Surirella
gemma can be resolved into dots, for they cannot ; they are so
extremely minute that they are by no means easy to detect.
To make them out at all a Tjyth. or xV^ n oil-immersion of
1ST. A. 1*3 is necessary, with eye-pieces of sufficient power to bring
the magnification up to at least 1,000 diameters, and often not
less than 2,000 diameters is really required to make the structure
clear, combined with very careful manipulation, a most exact
arrangement of the light and a fair stock of patience. Some can
be seen with central light, but for the most parti have found that
the easiest way to render them visible is by means of a Leitz
dark-ground illuminator, from which, by decentring it, various
modifications of oblique light and light reflected from the under
surface of the cover-glass can be obtained. This method of
reflecting light upon a diatom from the under surface of the
cover-glass may not be generally known, but it can be accom-
plished by decentring the condenser or dark-ground illuminator,
and then raising or lowering it slightly until the right effect is
produced. The process is not a difficult operation, but requires a
little practice, and very often features can be seen much more
clearly by this method than by any other. It is like viewing an
object upon which the sun is shining, with the back to the sun.
When examining a diatom by means of the Leitz illuminator no
funnel-stop must be used in the lens to cut down its aperture.
Sometimes a rather dim light is better than a bright one for
rendering the structure conspicuous.

The lowest power with which I have been able to see the pores
in the films of Pleurosigma balticum is Powell & Lealand's
excellent |-th water-immersion, with which, in combination with
a X 18 eye-piece, they are just perceptible. A Leitz ygth or
yg-th oil-immersion will also demonstrate them and those of
other species, but the lens I have chiefly used has been a Iteichert

N. E. BROWN ON THE STRUCTURE OF DIATOMS. 337

y^th oil-immersion of N.A. 1*3, on account of its greater
magnification, as it is really a xjth, not a true y^th.

Description of Plate 23.

Fig. 1. Part of one of the outer films of the outer grating of
Pleurosigma balticum, x 3,000. The central part from a camera-
lucida drawing, the remainder added to scale from various parts
of the films, to show the manner in which the bars project and
are held in place by the pore-perforated membrane of silex.
Realgar mount, central light, no stop.

Fig. 2. Part of a curved bar from a partly dissolved specimen
of Pleurosigma balticum, which presents both dorsal and edge
views, drawn as seen, to a scale of about 9,000 diameters.
Realgar mount, central light, no stop.

Fig. 3. Part of the grating of Swrirella gemma, x 3,000.
Realgar mount, central light, no stop.

Fig. 4. Four meshes of the same enlarged to the scale of 9,000
diameters.

Fig. 5. Fragment of the film overlaying the outer grating of
Pleurosigma angulatum, X 3,000. Realgar mount, Leitz dark-
ground illuminator, without a funnel-stop at the back of the
objective.

Fig. 6. Diagrammatic enlargement of the bars of the film
over the outer grating of P. angulatum, to show the manner in
which they appear to overlie one another, drawn to a scale
of 6,000 diameters. No pores could be seen when this appear-
ance is visible.

Fig. 7. Outer and inner grating of P. angulatum under the
film of diamond-shaped meshes, x 3,000. Realgar mount.

Fig. 8. Two meshes of the same enlarged to 9,000 diameters.

Fig. 9. Outer grating of P. angulatum, seen at the focus
immediately preceding the hexagonal appearance of fig. 7,
x 3,000. Realgar mount.

Fig. 10. Fragment of the grating of Xavicula serians, x 3,000.
Picric-piperine mount ; upper part showing the coarse inner
grating, as seen with central light and a central stop in the con-
denser, green screen ; lower part showing the outer grating
superposed upon the coarser grating, as seen illuminated by a
Leitz dark-ground illuminator^

338 N. E. BROWN ON THE STRUCTURE OF DIATOMS.

Fig. 1 1 . Fragment of the shell of Xitzschia scalar is, showing
pores, x 3,000. Styrax mount, central light, green screen.

Fig. 12. Fragment of the grating of Amphipleura Lindheimeri,
X 3,000. Styrax mount, central light, green screen.

Fig. 13. Fragment of the shell of a small species of Pinnularia
from the Cherryfielcl deposit, x 3,000, showing what are believed
to be a row of pores down the centre of the outer wall of each
cavity. Picric-piperine mount, central light and green screen ;
can also be seen with dark-ground illumination without a funnel-
stop in the lens and no green screen.

Fig. 14. Fragment of the grating of Stauroneis ])hoenicenteron,
x 3,000. Picric-piperine mount, oblique illumination by Leitz
dark-ground illuminator.

Fig. 15. View of one of the hexagonal cavities of the valve of
Triceratiam favus as seen from the outside of the diatom, showing
the membrane which closes it on the outer side, x 1,500. Styrax
mount ; outline drawn with a camera-lucida as seen under a
monocular, shading added as seen under a binocular with oblique
illumination.

Fig. 16. View of one of the hexagonal cavities of the valve of
Triceratium javus as seen from the interior of the diatom, showing
the raised appearance of the membrane, x 1,500. Styrax mount,
drawn in the same manner as fig. 15.

Fig. 17. Fragment of the membrane shown in fig. 16, drawn as
seen at a magnification of 3,000 diameters, but enlarged to about
10,000 diameters, to show the pit-like nature of the dots upon
the membrane.

Joi'.m. Qucl-ett Microscopical Club. Scr. 2, Vol. XII. No. 74, April 1914.

Jourx. O.M.C.

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Structure of Diatoms.

339

NOTICES OF BOOKS.

Handbook of Photomicrography. By H. Lloyd Hind, B.Sc,
F.I.C., and W. Brough Randies, B.Sc. 8| x 5 j in., xii +
292 pages, 44 plates and 71 text illustrations. London,
1913 : G. Rout ledge & Sons, Ltd. Price 7s. 6d. net.

The student of photomicrography, whether he approach the
subject from the side of photography or microscopy, can hardly
complain of the lack of manuals whose aim is to guide him
in this fascinating subject. The photographer, in reading
Messrs. Hind and Randies' handbook, may perhaps be surprised
that so much space is devoted to details concerning the micro-
scope and its accessories; but he must remember that in order
to photograph an object under the microscope it is very essential
he should possess the necessary knowledge of the instrument
to obtain the best results visually.

Although the subject is treated by the authors in an ele-
mentary manner, at the same time, however, the processes are
discussed in sufficient detail to be of use in research. A special
feature of the book is the very numerous illustrations, and with
each photomicrograph reproduced full details are given of the
process and apparatus used and the method of developing the
negative. This very useful feature enables any special worker
to select the best means for his own branch of the subject,
whether it be the photography of the minute details of diatoms,
the stained sections for use in the histology of plants and
animals, or rock sections and crystals under polarised light.
The subject of colour photomicrography is dealt with in
Chapter XIII. The utility of the Autochrome and Paget plates
for registering the appearance of thin rock sections under
polarised light was excellently demonstrated at a recent meeting
of The Photomicrographic Society.

The subject of cinema-micrography is referred to, but this
could hardly be dealt with fully in an elementary textbook.
In fact, as a means of research it is in its infancy, but fruitful
results may be expected in the future in the study of the
life-history and movements of micro-organisms.

There are useful formulae and tables at the end of the book
and an index. Both authors and publishers may be congratu-
lated on the appearance of the book.

Journ. Q. M. C, Series II. No. 74. 24

340

PROCEEDINGS

OF THE

QUEKETT MICROSCOPICAL CLUB.

At the 492nd ordinary meeting of the Club, held on October 28th,
1913, the President, Prof. A. Dendy, D.Sc, F.R.S., in the chair,
the minutes of the meeting held on June 24th, 1913, were read
and confirmed.

Mr. S. G. H. Knox was balloted for and duly elected a member
of the Club.

The Hon. Secretary said they were favoured with the presence
of several visitors, to whom he offered a hearty welcome on behalf
of the Club.

The President said that members would be sorry to hear that
since the last ordinary meeting the Club has sustained the loss of
one of our more well-known members : the Right Hon. Sir Ford
North, F.R.S., died on October 12th, at the age of eighty-three.
He was a Fellow of the Royal Society, and a keen entomologist.
He was elected a member of the Club in 1894, became a member
of the committee in 1899, and was one of the vice-presidents from
February 1901. His patience and experience in directing a
meeting when he occupied the chair made him a most valuable
member of the Club, and one whose loss will be much regretted.

Mr. E. J. Spitta said that Sir Ford North hardly ever missed
attending the meetings of the Club, and he thought that a more
charming man never existed. Often in committee he would
remain silent for a long time, and would then rap out a very
clever opinion on the matter before them. During the four years
of his (Mr. Spitta's) presidency he had frequent opportunities of
intercourse with Sir Ford North, and on every occasion had found
him a courteous friend.

Mr. Spitta then moved: "That the Committee be empowered
through the Secretary to convey to the relatives of the late Sir
Ford North an expression of their regret and sympathy."

This having been put to the meeting, it was unanimously
carried by the members present silently rising.

PROCEEDINGS OF THE QUEKETT MICROSCOPICAL CLUB. 341

The list of donations to the Club was read, and the thanks of
the members were voted to the donors.

Mr. S. C. Akehurst (Hon. librarian) read a note on "A
Changer for Use with Sub-stage Condensers." The method of
using the changer was demonstrated to the members.

Mr. S. C. Akehurst also read a note on " A Trap for Free-
swimming Organisms." Two forms of the little piece of apparatus
were exhibited, and details demonstrated by drawings on the
blackboard.

The President said he had examined the extremely ingenious
contrivance for quickly changing the condenser. It was a matter
which very strongly appealed to him, as he had often much
trouble in changing condensers.

Mr. D. J. Scourfield, referring to the trap for free-swimming
organisms, said this method opened new possibilities w T hen
dealing with extremely minute organisms. One can get to a
certain point with the centrifuge ; but it is sometimes desired to
go a little further in concentrating. He thought it a very
ingenious piece of apparatus.

A paper on " The Gastrotricha," communicated by Mr. James
Murray, F.R.S.E., was introduced by Mr. Scourfield, who said
that it was just twenty-four years since the subject had pre-
viously been brought before the notice of the Club. This was
a paper read by T. Spencer on September 27, 1889, on a new
species he provisionally named Polyarthra fasiforniis. This is
now Stylochaeta fusiformis. Mi 1 . Murray said that he had
been reluctant to attempt an introduction to the study of the
Gastrotricha, as his knowledge of the group was by no means
profound, and had been only recently acquired. The main part
of the paper is an annotated bibliography which it was hoped
would save students much of the trouble the author had ex-
perienced. If the bibliography be too condensed, the student is
always liable to suspect that a work omitted from it has not
come to the knowledge of the compiler. Here, however, all
important general, biological and systematic works known to
the author are included, as well as any really important
faunistic studies. Every work is given in which new, or sup-
posed new, species or groups of higher value are described. It
is unfortunate that the Gastrotricha which include those old
familiar friends of the students of pond-life, Chaetonotus lanes

342 PROCEEDINGS OF THE

and Ichthydium podura have no popular name. Gosse pro-
posed the name of " hairy-backed animalcules." This is entirely
unsuitable, since some of the genera are not hairy-backed
(Ichthydium, Lepidoderma). Mr. Murray was not able to suggest
an appropriate name. The name suggested by the scientific
term for the whole group, which embodies almost the only
character which they all possess, is unsuitable for popular use.
The Gastrotricha are not animals which can be named offhand.
The days when we found Chaetonotus lanes and Ichthydium
podura, occasionally varied by C. maximus, on all our pond-life
excursions are over. There is a host of species which have
contributed to the records of C. larus. These species are all
alike to a casual glance, but are distinguished by minute
characters the possession of small branches by certain of the
bristles, the form of the minute scales which bear the bristles,
etc. Some of these are so delicate that an oil-immersion lens
would be needed for their certain determination. The author
expressed his thanks to Messrs. Rousselet, Bryce and Starring
for assistance given in the preparation of this paper. The paper
then goes on to describe the form and structure of the Gastro-
tricha, their haunts and habits, an historical sketch of the
genera, their classification, a key to the genera and a list of
the eighty-three species which have been described, notes on the
identification of species and on some species Mr. Murray had seen,
and concludes with a bibliography of seventy-two items. Mr.
Scourfield illustrated his remarks and comments by references to
a number of sketches he had drawn on the blackboard.

The President had much appreciated Mr. Scourfield's resume
of Mr. Murray's paper. He referred to the " fish-hook " spines
and other extraordinary specific characters, which, he thought,
could not possibly be explained as due to natural selection. The
Club was very much to be congratulated on having such an
important paper contributed to the Journal.

Mr. llousselet said these organisms could be preserved quite
well in 5-per-cent. formalin. He remembered Mr. Spencer's
paper in 1889 quite well, and had differed from him at the
time, and had said fusiformis was not a rotifer, but could
not then say what it was. The animal was taken at a Club
excursion.

On the motion of the President a cordial vote of thanks was

QUEKETT MICROSCOPICAL CLUB. 343

passed to Mr. Murray for his paper and to Mr. Scourfield for
giving them so good a resume of it.

Mr. James Grundy described and exhibited "An Improved
Form of Cheshire's Apertometer."

Mr. Grundy said that of the value of Mr. Cheshire's form of
apertometer there can be no doubt. The aim of Mr. Nelson has
been to enable the N.A. values of an objective to be read on the
apertometer easily and accurately. Distinctness and clearness of
reading have been effected by increasing the number of marked
values of N.A. from 9 to 22 without the confusion that over-
crowding of the lines would entail. To accomplish this, short
arcs of circles are used instead of whole circles. A valuable pro-
perty of these is the clear visibility of the ends or edges of the
arcs : they are seen more distinctly than complete circles would
be. The contrast between the white ground and the short black
lines favours this. The exterior edges of the arcs denote the N.A.,
and thus give most convenient, accurate, and definite positions for
reading.

Mr. F. J. Cheshire said it might interest members to know
that he described his apertometer before the Club some ten years
ago. When Zeiss first issued Abbe's form, it was marked to read
only to 005. In a paper defending this marking, read before the
R.M.S. in 1880, Abbe dealt with the accuracy it was necessary
to strive for. On the Zeiss apertometer it is possible to read to
| per cent. ; but blue rays alone will give a difference of 1 per
cent, over a reading taken with red light, so that the maximum
accuracy it was advisable to attempt to obtain was 1 per cent.
Mr. Cheshire thought that one point in Mr. Nelson's diagram
largely vitiates the advantages given by a greater number of
fiducial Hues that is, that the fiducial edge in the diagram is
the outer edge of the line ; and, again, the lines are of varying
thickness. There are twenty-two edges of lines on the diagram
with no fiducial value. He himself thought that his original
form was not capable of further accuracy. Mr. Cheshire then
described, and subsequently demonstrated, another method of
measuring N.A., which he considered an improvement on the
older form.

A visitor Mr. M. A. Ainslie, K.N. said that experience in
the use of both the original form of Cheshire's apertometer and
the modification thereof recently suggested by Mr. Nelson has

344 PROCEEDINGS OF THE

revealed one or two difficulties in connection with the reading of
the instrument that is, if any accuracy in the second decimal
place is required. The first difficulty is due to the fact that in
Mr. Cheshire's instrument we have to interpolate or estimate
between two divisions on a scale, one of which is not visible, being
outside (apparently) the margin of the back lens of the objective.
This renders the estimation of the second place of decimals in the
N.A. uncertain,' and although Mr. Nelson's modification of the
original instrument is somewhat better in this respect, yet the
very means adopted to improve the reading namely, the intro-
duction of a large number of additional circles is likely to con-
fuse the diagram and bewilder the observer. In either the old
form or the new of Cheshire's instrument, a count has to be made
of concentric circles a thing which, simple as it may seem, is
peculiarly liable to confuse the eye, so that it is only after count-
ing several times that one feels certain that the number is, say,
eight, and not seven.

Mr. Ainslie exhibited and described a new method of reading
the N.A. of an objective,

The President said the Club was much indebted to Mr. Ainslie
for his communication, and also to Mr. Cheshire and Mr. Grundy,
to whom the thanks of the meeting were unanimously voted.

At the 493rd ordinary meeting of the Club, held on Novem-
ber 25th, 1913, the President, Prof. A. Dendy, D.Sc., F.R.S.,
in the chair, the minutes of the meeting held on October 28th,
1913, were read and confirmed.

Messrs. W. M. Bale, B. Shepherd, H. Dobell, E. W. Ramsay,
M. R. Licldon, A. Panichelli, Robert Young, W. G. Tilling, and
E. J. E. Creese were balloted for and duly elected members of
the Club.

The President read a letter from the nephew of the late Sir
Ford North, which was in reply to the vote of sympathy passed
at the last meeting.

Mr. C. E. Heath, F.R.M.S., brought before the notice of the
meeting a device for preventing damage to objective or slide,
especially when the higher powers are used, in cases where the
microscope is liable to unskilful usage, as, e.g., at soirees. A
small piece of thin metal steel was suggested is taken, having

QUEKETT MICROSCOPICAL CLUB. 345

a hole in it of such a size as to permit of the screw-end of an
objective passing through it up to its flange. In use the plate is
placed over the end of the nose-piece, and the objective screwed
home through it. To a projecting portion of the metal plate is
fitted a short length of brass tube or rod say | in. diameter,
which has been tapped internally, the direction of the tube being
parallel to the optic axis, and just clear of the objective. A fine
screw (25 threads to an inch) is fitted to the tube, and at the
lower end is provided with a milled head. The microscope is
focused in the usual way, and the screw then screwed down until
it is in contact with the stage clear of the cover-glass, and so
prevents any movement of the body, and possible damage. If
required, a small amount of slack may be left for possible focusing
by visitors who can use a microscope.

The President described " A Red- Water Phenomenon due to
Euglena." He had noticed a curious appearance in a pond near
Manchester : the water was of a brilliant red colour. This, on
examination, proved to be due to Euglena, which formed quite a
thick scum of the red colour. The colour was confined to the
surface, and had a dry, powdery appearance that was very notice-
able. Microscopic examination showed the Euglena to be of a
large species, and the red coloration to be due to the replace-
ment of the chlorophyll by haematochrome. The main mass of
the body was coloured. Those floating on the surface were in a
resting condition ; but, at the bottom, all were actively swimming
about. There was apparently no intermediate stage, and at once
the question arose : How did the organisms get from the bottom
to the top of the pond % It was found that the Euglenae at the
bottom of the pond secreted large quantities of mucilage. The
organism, in the presence of sunlight, gave off bubbles of oxygen,
which became entangled in the mass of mucilage, and presently
carried the mass to the surface, trailing Euglenae after it, so that
they were collected at, and formed a scum on, the surface. The
colour of the scum changed during the day, from red in the
morning to green in the afternoon, the actual change from one to
the other being accomplished in about half an hour. Cunning-
ham had observed similar changes in Euglena viridis, near
Calcutta, lie records the scum as bright red in the morning
dull red at midday, and green in the evening, and by sunset an
intensely vivid green. The reverse took place just about dawn,

346 PROCEEDINGS OF THE

so that at sunrise the pond scum was brilliant red again. The
President asked if any members had seen a similar appearance.

Mr. C. F. Rousselet, when in South Africa with the British
Association in 1905, had noted near the Matoppo hills a similar
red Euglena, which he had not before seen.

The Hon. Sec. paid considerable attention to the " Breaking of
the Meres," but had never seen red Euglena. He had observed
red scum, due to other causes. The phenomenon noticed by the
President was, however, not unique in this country. Some years
ago he had received some " red scum " material from Norfolk,
which was definitely identified as Euglena. The organisms were
crowded in their middle region with starch grains, and starch in
such a form that it was not affected by iodine.

Mr. A. E. Hilton asked whether the red colour indicated the
decay of the chlorophyll formed during the previous day.

The President did not think that the change from green to red
indicated any process of decay this change of colour was not
unique in Nature, as the snow plant could be obtained both red
and green, and apparently the change was due to nitrogen starva-
tion. He found this to be the probable cause when he had two
jars side by side, one red and the other green, and a fly had
fallen into one jar and had decayed ; the slightest trace of nitro-
genous food was sufficient to cause the change, which he thought
could not be regarded as a product of decomposition. Dr.
Cunningham thought that both kinds of pigment were present at
the same time, but that they were differently placed when the
change of colour was observed ; but whether this was the sole
reason for the change in the Euglenae was not certain.

Mr. James Burton (Hon. Secretary) read a short paper,
" On the Disc-like Termination of the Flagellum in certain
Euglenae."

Mr. James Burton also read a note on " A Method of Marking
a Given Object on a Mounted Slide."

Mr. M. Blood said he usually put a spot of ink on the bright
spot of light formed on the slide by a high-power condenser, and
when it was dry, scraped the centre away.

Mr. Spitta, after finding and centring the object in the field,
replaced the objective with a dummy of similar size, on to the lower
end of which had been fastened a rubber letter 0, such as is to be
obtained in small movable-type printing outfits. The letter is.

QUEKETT MICROSCOPICAL CLUB. 347

inked, and gently lowered on to the slide. He had found this
method quite satisfactory.

Mr. James Grundy read a paper communicated by Mr. E. M.
Nelson on " The Measurement of the Initial Magnifying Powers
of Objectives." Mr. Grundy added a few notes in amplification
and explanation of some points in Mr. Nelson's paper, which he
illustrated with blackboard diagrams.

A vote of thanks to Mr. Grundy was carried unanimously.

At the 494th ordinary meeting of the Club, held on December
23rd, 1913, Mr. D. J. Scourfield, F.Z.S., F.R.M.S., Vice-
President, in the chair, the minutes of the meeting held on
November 25th, 1913, were read and confirmed.

Messrs. M. A. Ainslie, R. A. Saunders, T. B. Lock, F. S.
Mumford, A. Green, H. F. W. Sprenger, W. D. Deed and J. H.
North were balloted for and duly elected members of the Club.

A letter was read from the Poyal Microscopical Society
enclosing a copy of a resolution passed by their Council, thanking
the members of the Q.M.C. who exhibited at their Conversazione
on November 19th.

Mr. B. M. Draper read a paper on a new live box for the
exhibition of flies and other large objects under low powers of the
microscope the article itself being exhibited in the room under a
Greenhough binocular.

Mr. B. M. Draper also read a paper describing a new stop for
obtaining dark-ground illumination with the Greenhough
binocular the subject being illustrated by the exhibition of the
stop and by a diagram upon the blackboard.

The Chairman thought the live box well adapted for showing
large objects, and inquired if any means were adopted for con-
fining the insects or controlling their movements whilst under
observation.

Mr. Draper said there was no other means of controlling the
movement of the objects except by the use of a small cell, but
the power used being a low one, the whole cell was generally in
the field at the same time ; and in answer to a question by
Mr. Rousselet, he said that the cover of the cell was only held
down by its own weight, but it was prevented from slipping
sideways by the upright pins mentioned in the paper.

q

48 PROCEEDINGS OF THE

The thanks of the meeting were voted to Mr. Draper for his
papers.

Mr. W. R. Traviss exhibited under microscopes two fragments
of quartz crystals. Referring to one of the mounts, he said it
showed a series of seven faint lines across the field, parallel, but
not equally spaced. He suggested that the lines at one time
were respectively the outer surfaces of the crystal. The plane
of this particular surface in the mount referred to was at right
angles to the plane of the microscope stage, so that by focusing
down one could look along this plane. It was then noted that
this " old crystal surface " was covered with a number of very
small crystals, or debris, which had been deposited on this plane.
Presently the crystal went on growing, and again a period of rest
and more debris deposited or formed. This was repeated seven
times, but the exterior face was quite smooth.

Then as to the occasional presence of contained bubbles of
liquid in quartz (and other) crystals. It was suggested that it
was possible that they were formed by a bubble of gas adhering
to perhaps the under surface of a growing crystal, and material
being deposited round and over it.

Some discussion followed on liquid enclosures in crystals and
the nature and method of identification of the gases contained.
The chairman drew attention to a paper by Mr. Ashe on the
effects of temperature on enclosed liquids. (Journ. Q. M. C, Ser.
2, Vol. VIII., pp. 545-8, pi. 28.)

Mr. E. M. Nelson sent a note on a peculiar form of diatom.
During an examination with dark-ground illumination of Mr.
Siddall's filaments on some Coscinodisci in a diatom gathering,
mounted and kindly given me by Mr. Chaffey, a small portion
of sandy grit was found to have similar filaments protruding from
it. Its colour was a golden yellow, the same as the sandy grit
usually seen in this kind of slide, which contains diatoms mounted
in sea-water in their natural state. The dark-ground illumi-
nator was removed, and when the object was examined by an
oil-immersion gth with transmitted light from an achromatic
condenser, the green chlorophyll pustules of a diatom could just
be made out inside the conglomerated mass of sandy grit. A
search was then made over the slide, and three or four other
similar specimens were found. So it appears, then, that there is
a " caddis-worm " form of a diatom. What species this diatom

QUEKETT MICROSCOPICAL CLUB. 349

may be no one can say, for it cannot be seen with sufficient dis-
tinctness for identification. Probably in its cleaned state it may
be a very common and well-known form, but had it not been for
its filaments, its presence in these sandy conglomerations would
never have been suspected. Other species of diatoms on this slide
were quite free from sandy grit.

Mr. Nelson ako sent a note on Amphipleura Lindheimeri.

At the 495th ordinary meeting of the Club, held on January
27th, the President, Prof. A. Dendy, D.Sc, F.R.S., in the
chair, the minutes of the meeting held on December 23rd, 1913,
were read and confirmed.

Messrs. H. A. Gee, G. H. Shelley, A. Walker, the Rev. G. H.
Nail, Lieut.-Col. J. Clibborn and L. E. Harris were balloted for
and duly elected members of the Club.

The list of nominations by the Committee of officers for the
ensuing year was then made there being no change from that
elected last year.

The President having mentioned that four members of the
Committee Messrs. Wilson, Heron- Allen, Bryce and Caffyn
would retire by rotation, but were eligible for re-election, except
Mr. Caffyn, who did not wish to serve again, asked for nomina-
tions of members to fill the vacancies created.

The following gentlemen were thereupon nominated : Messrs.
Heron -Allen, Wilson, Bryce, Gabb, A. Morley Jones and Todd,
whose names would appear on the voting paper at the next
ordinary meeting.

Mr. A. E. Hilton was then elected as Auditor on behalf of the
members.

Mr. S. C. Akehurst (Hon. Librarian) read " Some Remarks on
Sub-stage Illumination " ; the subject was illustrated by a number
of photographs projected upon the screen.

Mr. T. A. O'Donohoe read a paper, entitled "An Attempt to
resolve Pinnularia nobilis" This was illustrated by photographs
projected upon the screen.

Mr. M. A. Ainslie said that the whole question of diffraction
spectra was of course of vital importance in the resolution of any
fine structure, and in many cases it could not be done with a dry
lens. By means of diagrams drawn on the blackboard as he pro-

350 PROCEEDINGS OF THE

ceeded, the speaker showed the effects of diffraction spectra under
varied conditions. In using annular illumination they were
using a number of central cones of illumination overlapping to
form the annular. He also pointed out the danger of using
annular illumination unless great care was exercised as to the
tube length.

Mr. Blood said it was extremely easy to resolve diatoms with a
central stop in which case they were merely seeing the image of
the stop. In many objectives the central portion and the
extreme edge were over corrected, but the intermediate zone was
quite right.

Mr. Brown said he had been examining Pinnularia nobilis for
the last forty years, and thought he had obtained a resolution of
it, but not the same as that described by Mr. O'Donohoe. For a
long time he was unable to get any resolution, but he believed he
had now done so, and hoped shortly to read a paper on the subject.

Mr. Akehurst explained that the photographs shown in illus-
tration of his paper were taken to show the contrast between the
ordinary and the new method of illumination with central stop
below the condenser, but without cutting down the N.A. of the
objective.

Votes of thanks were cordially passed to Mr. Akehurst and
Mr. O'Donohoe for their papers.

In place of the usual monthly conversational meeting, a Conver-
sazione was held on February 10th, in the Great Hall, King's
College, by kind permission of the Principal. Nearly five hundred
members and visitors were present, and about 170 microscopes,
besides other apparatus, were on exhibition. It is not possible to
give a complete list of the objects shown ; but among others may
be mentioned a number of coloured drawings of water-mites,
including a series of fifteen figures illustrating the life-history of
Hydrachna ylobosa (de Geer), by C. D. Soar ; foraminifera under
microscopes, and material from the sea-bottom in various stages
of preparation, by Messrs. Heron-Allen and Earland ; living-
rotifers by Messrs. Bryce, Dunstall, Rousselet, Scourfield and
others ; stereophoto-micrographs by Messrs. A, E. Smith and
Taverner ; photomicrographic apparatus and some sixty natural-
colour lantern-slides by E. Cuzner ; some fine photomicrographs
in colour of polarised rock sections by Messrs. Cafiyn and Ogilvy.

QUEKETT MICROSCOPICAL CLUB. 351

Mr. H. F. Angus (H. F. Angus & Co.) showed the Reichert
demonstration and comparison eye-piece for comparing the fields
from two microscopes in one eye-piece, in which the field is divided
laterally, Akehurst's phototropic pond-life trap, Draper's all-glass
live box, the Finlayson revolving disc for the exhibition of a
series of opaque objects, Heath's objective-guard, etc.

Mr. Lees dirties (C. Baker) had on view several Greenhough
binocular microscopes, multicolour illumination of crystals, and
three forms of the Cheshire apertometer.

Mr. C. Beck (R. & J. Beck) exhibited the new model high-
power binocular, employing a -jVth oil-immersion objective, with
a very simple and efficient adjustment for inter-pupillary
distance.

Mr. J. W. Ogilvy (E. Leitz) showed several new short-tube
high-power binoculars employing a T Vth oil-immersion objective ;
a comparison eye-piece for comparing simultaneously complete
fields of two microscopes; and several examples of the Green-
hough binocular one especially adapted for metallurgical work.

Mr. F. W. W. Baker (W. Watson & Sons) exhibited a new
model Yan Heurck, with 2| in. movement to the stage, and
complete rotation, also a new workshop metallurgical microscope
and some twenty microscopes with various objects, including a
series of seven illustrating the development of the chick from
twenty-four hours to four clays.

During the evening a lantern lecture was given in the large
theatre by Mr. F. W. Watson Baker (Watson & Sons) on " Some
Microscopical Hows," and subsequently Mr. C. Lees dirties
(C. Baker) gave a lantern demonstration, in the same place, of
natural-colour photographs and photomicrographs of miscellaneous
and microscopic objects prepared by the Paget process. Both
lectures were well attended and much appreciated.

Of late years the club has not held conversaziones, and during
the evening the wish was several times expressed that such
gatherings should be more frequent, and certainly that no long
interval should elapse between this and the next. (The last
conversazione was held nearly seventeen years ago on May 4th,
1897 in the smaller Queen's Hall.)

352

PROCEEDINGS OF THE

At the 496th ordinary meeting of the Club held on February
24th, which was also the forty-eighth annual general meeting,
the President, Prof. A. Dendy, D.Sc, F.R.S., in the chair the
minutes of the meeting held on January 27th were read and
confirmed.

Messrs. A. 0. Gooding and Raymond Finlayson were balloted
for and duly elected members of the Club.

The list of donations to the Club were read, and the thanks of
the members voted to the donors.

Mr. N. E. Brown and Mr. F. W. Watson Baker having been
appointed scrutineers, the ballot for the election of officers and
Council for the ensuing year was proceeded with ; it being sub-
sequently announced that the following gentlemen had been
elected as

President

Four
Vice-Presidents

Treasurer
Secretary

Assistant Secretary
Foreign Secretary .
Reporter ....
Librarian . . .
Curator ....
Editor ....

Four Members of
Committee.

Prof. Arthur Dendy, D.Sc, F.R.S.

C. F. Rousselet, F.R.M.S.

E. J. Spitta, L.R.C.P., M.R.C.S., F.R.A.S

D. J. Scourfield, F.Z.S., F.R.M.S.
IProf. E. A. Minchin, M.A., Ph.D., F.R.S.

Frederick J. Perks.
James Burton.
J. H. Pledge, F.R.M.S.
C. F. Rousselet, F.R.M.S.
R. T. Lewis, F.R.M.S.
S. C. Akehurst, F.R.M.S.

C. J. Sidwell, F.R.M.S.

A. W. Sheppard, F.Z.S., F.R.M.S.
(A. Morley Jones.

E. Heron-Allen, F.L.S., F.Z.S., F.R.M.S.
J. Wilson, F.R.M.S.

D. Bryce.

The Hon. Secretary read the Committee's forty-eighth annual
report. Fifty-five new members were elected during the past
year, and the total number is now 441.

The Hon. Curator reported that 2,000 slides had been borrowed
by members, and that 192 preparations had been added to the
collection during the past twelve months.

The Hon, Treasurer presented the Annual Statement of

QUEKETT MICROSCOPICAL CLUB. 353

Accounts and the Balance Sheet for 1913, which had been duly
audited and found correct.

The adoption of the Committee's report and the Balance Sheet
was moved by Mr. A. M or ley Jones and seconded by Mr.
Morland and carried unanimously.

Mr. D. J. Scourfield, F.Z.S., F.R.M.S., Vice-President, having
taken the chair, the annual address was delivered by the President,
who took as his subject " Organisms and Origins."

The usual votes of thanks to the President for his address, and
to the officers of the Club for their services during the past year,
were carried by the meeting. A special vote of thanks was
passed to the Hon. Secretary and to Mr. J. Grundy for their
services in so successfully organising the recent conversazione.

354

FORTY-EIGHTH ANNUAL REPORT.

Your Committee are glad to be able to assure the Club of its
continued prosperity. During the year ending December 31st,
1913, fifty-five new members were elected ; this number has been
equalled only once, and exceeded only once when there were
fifty-seven elected during the recent years of which any record
has been found. Eleven have resigned, and four were lost by
death, leaving the present number 441. Among those lost by
death should be mentioned the Eight Hon. Sir Ford North, for
some years a Vice-President and a valued member of the Club.
An obituary notice appeared in the November number of the
Journal.

Both the Ordinary and Gossip Meetings have been well attended,
in fact on several occasions the number present was somewhat
more than the capacity of the room would accommodate with
a due regard to comfort.

The papers and notes read and exhibits contributed during the
year were as follows :

Jan. W. M. Bale, F.B.M.S., of Victoria, Australia. Notes

on some of the Discoid Diatoms. Communicated by
the President.
H. Whitehead, B.Sc. British Freshwater Bhabdo-

coelida (Planarians). Communicated by J. Wilson.
C. F. Bousselet, F.B.M.S. The Botifera of Devil's

Lake : Description of a New Brachionus.
E. M. Nelson, F.B.M.S. Note on Pleurosigma angu-
latum ; Note on a Coloured Coma observed in
examining A. Ralfsii.
Feb. Prof. A. Dendy, D.Sc, F.B.S. By-products of Organic

Evolution. Presidential Address.
March. E. Heron-Allen, F.Z.S., F.L.S., and A. Earland,
F.B.M.S. On some Foraminifera from the Southern
Area of the North Sea, dredged by the Fisheries
cruiser Huxley.
n D. Bryce. Five New Species of Bdelloid Botifers.

j?

>>

55

FORTY-EIGHTH ANNUAL RETORT. 355

April 0. D. Soar, F.L.S., F.R.M.S. Two New Species of
Water-mites.
,, G. T. Harris. The Collection and Preservation of the

Hydroida.
May. T. A. O'Donohoe The Minute Structure of Coscino-
discics asteromphalus and of two Species of Pleuro-
sigraa.
June. H. Sidebottoin. The Lagenae of the South-West
Pacific.
E. M. Nelson, F.R.M.S. On a New Method of Mea-
suring the Magnifying Power of an Objective.
Oct. James Murray, F.R.S.E. The Gastrotricha.

,, E. M. Nelson, F.R.M.S. Note on an Improved Form of

Apertometer.
Nov. James Burton. On the Disc- like Termination of the
Flagellum in some Euglenae.
James Burton. On a Method of Marking a Given

Object on a Mounted Slide for Future Reference.
E. M. Nelson, F.R.MS, On the Measurement of the
Initial Magnification of Objectives.
Dec. B. M. Draper. On Dark-ground Illumination with the

Greenhousdi Binocular.

>)

n

D

At the Ordinary Meetings the following slides and apparatus
were exhibited :

Jan. W. Watson Baker. New Model Microscope, having a
Side screw Fine Adjustment, and New Objective
Changer, etc.
A. A. C. Eliot Merlin, F.R.M.S. Photomicrographs of

Coscinodiscus heliozoides, showing Pseudopodia.

March. A. A. C. Eliot Merlin, F.R.M.S. Five Photomicro-
graphs taken at x 320 of various Diatoms.

April. Presented by G. T. Harris. Mounted Hydrozoa, ex-
hibited under Microscopes by Messrs. H. F. Angus
&Co.

May. J. Watson, a visitor. A Slide showing Multiple Images
formed by the Cornea of the Eye of a Bee.
E. Pitt. Various Microtomes exhibited and explained,

3>

with Demonstration of Ribbon Section-cutting

Journ. Q. M. C, Series II. No. 74. 25

)

"

o56 FORTY-EIGHTH ANNUAL REPORT.

June. A. A. 0. Eliot Merlin, F.R.M.S. Photomicrograph of
Foot of Ceylon Spider.
E. M. Nelson, F.R.M.S. A Slide of Green Trap show-
ing Structure resembling Vegetable Tissue.
,, W. Traviss. Apparatus for Use in Pond Hunting,

enabling a Sample of Water to be obtained at any
desired Depth.
,, James Grundy. Apparatus for use in connection with

E. M. Nelson's paper " On a Method of Measuring
the Magnifying Power of an Objective."
Oct. S. C. Akehurst. A Changer for Sub-stage Condensers.

S. C. Akehurst. Trap for Minute Free-swimming

Organisms.
Messrs. Grundy, Cheshire and Ainslie. Various Aper-
tometers.
Nov. C. E. Heath, F.R.M.S. Objective Guard for Preventing

Damage to High-power Objectives.
Dec. B. M. Draper. A New Form of Transparent " Live
Box " for the Exhibition of Living Organisms, chiefly
Insects. Also a Special Form of Stop for Dark-
grouncl Illumination with a Greenhough Binocular.
W. Traviss. Specimens of Quartz showing under the

Microscope a Laminated Structure.

Your Committee feel that the Club is greatly to be congratu-
lated on the inclusion in its Journal of such valuable papers.
Not only is their publication in our Proceedings an honour to the
Club, but the actual value of the communications as a contribu-
tion to science, and especially to that always difficult and often
little-appreciated subject, classification, makes the Journal a
standard work of reference. The Club has also been the means
of making known and recording a number of new species among
the Rotifera, the Entomostraca, and Water-mites, by members
who are authorities in these several classes. While thanking
those members who have contributed to the success of the Club,
the Committee would take this opportunity of urging upon
others the great advantage of bringing before the Club subjects of
interest in the form of short papers or notes, and the profit they
would themselves obtain by putting their knowledge into the
concrete and definite shape required for this purpose. The

FORTY-EIGHTH ANNUAL REPORT. 357

Committee at the same time wish it to be remembered that one
of the foremost aims of the Club is to assist the amateur and the
beginner, both by providing papers of a somewhat elementary
character, and by assuring them that, particular]}' at the Gossip
Meetings, they will find friends willing and anxious to assist them
in their efforts in gaining experience in the best methods of using
their instruments, and in the task of identifying specimens.

The Librarian reports that there has been a fair demand for
books during the year, but somewhat less than that for 1912.
The card index and the numbering and rearrangement of the
books are nearly completed, and the path cleared for commencing
the final details of the new edition of the Catalogue. The
thanks of the Club are due to Messrs. Caffyn, Todd and L. C.
Bennett for the great amount of assistance they have given the
Librarian in these matters.

During the year under review the following volumes have
been added :

LIST OF BOOKS PURCHASED SINCE JANUARY 1913.

British Parasitic Copepoda. T. & A. Scott. Vols I. and II.
Ray Society.

Bibliography of the Tunicata, 1469 1910. J. Hopkinson.
Ray Society.

Schmidt's Atlas der Diatomaceen-kunde. 4 Vols.

Light. (For Students ) Edwin Edser.

British Rust Fungi. N. B. Grove.

LIST OF BOOKS PRESENTED SINCE JANUARY 1913.

Presented by the Author, Dr. Eugene Penard :

Nouvelles recherches sur les Amebes du Groupe
Terricola.

Presented by the Publisher, John Murray :
Problems of Life and Reproduction . . Marcus Hartog.

Presented by J. Burton :
Das Phytoplankton pes Susswassers.

358 FORTY-EIGHTH ANNUAL REPORT.

Presented by the Author, Henry Whitehead.
British Freshwater Leeches.

Presented by Prof. Arthur Dendy :
Classification and Phylogeny of the Calcareous

Sponges . . . Arthur Dendy, D.Sc., F.R.S., and

R. W. Harold Row, B.Sc.

With a reference list of all the described species systematically
arranged.

Presented by the Author, Charles Janet, Limoges :
Le Volyox and Other Papers.

Presented by the Authors, E. Heron-Allen and A. Earland.
Clare Island Survey : Royal Irish Academy.
Part 64, Foraminifera.

Presented by the Author, J. W. Gordon :
Diffraction Images.

Daring the year ending December 1913 the Library has
received the following publications :

Quarterly Journal of Microscojncal Science.

Victorian Naturalist.

Mikrokosmos.

Royal Microscopical Society.

British Association.

Royal Institution.

Geologists' Association.

Manchester Literary and Philosophical Society.

Hertfordshire Natural History Society.

Birmingham Natural History and Philosophical Society.

Botanical Society of Edinburgh.

Glasgow Naturalists' Society.

Croydon Natural History Society.

Indian Museum (Calcutta).

Royal Society of New South Wales.

American Microscopical Society.

Smithsonian Institution.

Academy of Natural Science, Philadelphia,

FORTY-EIGHTH ANNUAL REPORT. 359

Missouri Botanic Garden.
Philippine Journal of Science.
Bergen Museum.
Lloyd Library, Cincinnati.
United States National Herbarium.
Royal Society. Series B.
Natural History Society of Glasgow.
Zoologisch-botanischen Gesellschaft, Wien.
Redia.

United States National Museum.
Nuova Notarisia.
Nyt Magazine.

Liverpool Microscopical Society.
Nova Scotian Institute of Sciences.
Royal Dublin Society.
University of California.

Illinois State Laboratory of Natural History.
Societe Royale de Botanique de Belgique.
Brighton and Hove Natural History and Philosophical

Society.
Essex Naturalist.
Edinburgh Royal Botanic Garden.

Northumberland and Durham Natural History Society.
Torquay Natural History Society.

There were twelve Excursions during the year, which were well
attended, the average number present being 20'8. That to the
Botanic Gardens had the most numerous visitors, namely 35,
and second to that the grounds of Syon House, Isle worth, with
33. Though no new species appear to have been recorded at the
outings, abundant and interesting material was acquired, and as
always the Excursions were marked by a spirit of comradeship
and social friendliness, as well as being an opportunity for
scientific acquisition. It may perhaps be pointed out that scarcely
as much use is made of the results of the excursions on the
subsequent Gossip Meetings as is desirable. Our thanks are due
to the officers of the Botanic Gardens, the East London Water
Works, and the Surrey Commercial Docks, for their kindness in
allowing the Club to visit their enclosures for collecting, and
to the Duke of Northumberland for permitting, through the

360 FORTY-EIGHTH ANNUAL REPORT.

kind intervention of his agent, the successful visit to the grounds
of Syon House. The objects exhibited at the Gossip Meetings
have been interesting and sometimes noteworthy, but it may be
well to impress upon new members, and beginners especially, that
all should make an effort to bring a microscope and some object
for display on these occasions. Not only is this a duty owed
to their fellows, but a distinct advantage to themselves; they
thus become expert in the use of their instruments and in the
arrangement of their specimens.

The work of the Curator, carried on for so many years, recently
under great difficulty owing to ill health, and to the insufficient
space at his command, is beyond all praise, and the best thanks of
the Club are hereby tendered to him for his self-denying labours.
The Curator reports that all slides and apparatus in his charge
are in good condition, and during the past year a great deal of
time has been spent in revision and amalgamation of the collec-
tions. There has been a considerable increase in the number
of preparations borrowed, upwards of 2,000 having gone out, and
even then the number has been unavoidably restricted owing
to cramped storage accommodation. 192 slides have been added,
72 of them by purchase. The beautiful physiological prepara-
tions, accompanied by descriptive letterpress and illustrations,
issued by Dr. Sigmund, of w T hich six series have been added,
have been in great request. A gap has been filled by the
presentation of a series of slides, with illustrated description, by
Mr. Whitehead, of Turbellarian Worms, a group previously un-
represented in the cabinets. A type collection of Hydrozoa,
presented by Mr. Harris, has been put to practical use, and, now
that his accompanying paper has been printed in the Journal, is
likely to be still further in demand. It is hoped by the issue of
additional descriptive sets to still further increase the usefulness of
the cabinets from an educational point of view. With the kind
co-operation of Mr. Vogeler the Curator has been able to issue a
supplementary list of part of the botanical preparations added
since the general catalogue was printed. The hearty thanks of
the Club are due to Mr. Vogeler for his kind services in printing,
also to Mr. Bestow for general assistance rendered the Curator,
and to the various donors of slides. The Committee desires to
thank the officers generally for the interest they have evinced,
and the often hard work they have undertaken in carrying on the

FORTY-EIGHTH ANNUAL fcEPOfct. 361

business of the Club so successfully. The thanks of the Club are
due to the editors of The English Mechanic and of Knowledge
for the reports of the proceedings published in their papers.

Finally the Committee feel that the Club may look forward
with all confidence to the future. Enthusiasm and work are
the means for continuing and increasing the success that has
attended it from its commencement, and also the means of
enabling us next year to celebrate the Jubilee of its foundation
in 1865, by men some of whom happily are still with us to
note with pride the growth and vitality shown by the Club
they inaugurated almost half a century ago.

362

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A NEW OBJECT GLASS BY ZEISS, AND A NEW
METHOD OF ILLUMINATION.

By Edward M. Nelson, F.R.M.S.
{Read March 24///, 1914.)

Figs. 1-3.

As Object Glass upon an entirely new plan has been brought
out by the firm of Carl Zeiss. This lens has not yet been
catalogued, but as it will undoubtedly effect a considerable
change in the construction and use of microscope objectives a
short account of it may prove of interest to the Club.

The object glass is a short tube oil- immersion 1 of "9 1ST. A.
Upon taking it out of its black box the first thing that will be
noticed is that it is nickeled all over, and the next is that the
front lens is set in a push tube, and not screwed up as usual ;
these two new departures from the usual type are also found in
the oil-immersion T Vth recently issued by this firm.

In very early times objectives were made on this plan. Both
Ross and Smith, before 1840, used to screw the front lens to a
tube, which was pushed on to another holding the back lenses ;
this tube was then rotated until the best point was found, when
a small screw was put in at the side to keep the tube in that
position.

This form of construction has gone on continuously to the
present day, especially in the cheaper series of objectives, while
the more expensive ones, including oil-immersions, have had the
cells holding the lenses screwed into their proper positions. But
this type of objective, so far as I am aware, for an oil-immersion
is quite new, as also is an oil-immersion with a N.A. of less than
1'0. Now with regard to the performance of this lens, the
corrections are very perfect ; although no fluorite is used in its
construction it is very nearly apochromatic, and shows a consider-
able advance over semi-apochromatism, for only a slight trace of
outstanding blue can be seen.

The defining power of this objective is quite remarkable, for it
surpasses all object glasses of similar aperture I have seen.

On a M oiler's Probe-platte of 60 diatoms all are resolved except

Journ. Q. M. C, Series II. No. 75. 26

364 E. M. NELSON ON A NEW OBJECT GLASS BY ZEISS,

the two specimens of Amphipleura pellacida. The next most
difficult diatom to the Amphipleura is the Nitzschia curvula, and
as this diatom counts 89 thousand per inch it shows what this new
lens can do with oblique light and a stop, the illuminant being
an ordinary microscope paraffin lamp with a \ in. wick. With
axial light, without any stop, the Brazilian Lindheimeri is dotted.
On M oiler's Typen-platte, with 400 forms, the Nitzschia curvula
(there called the JV. sigmatella) is very thin and difficult, and the
lens fails to resolve it, but it easily resolves all the others on that
line except the Homoeocladia Martiniana, which is more difficult
than A. pellucida. It resolves the N. crassinervis on that plate
quite easily, and it will just show the striae on the Grammatophora
oceanica, which counts 88 thousand to the inch. This diatom is
probably the G. subtilissima ; anyhow, it is very much finer than
the diatom of the same name on the Probe-platte.

The image given by this new lens of the Poclura scale is very
fine indeed. Undoubtedly in this new objective we have a lens
of great beauty and power. An important question arises as to
the influence this lens will have upon our battery of objectives.

In former times a 2 in., 1 in., a | in., a | in. and ^ in. or
yg- in. represented a full battery, but now we may have a
battery consisting of only a | in. and an oil-immersion T V in.
Here the gap is very wide, and the new lens will fill it very
satisfactorily.

This lens will, to a certain extent, supersede the oil-immersion
T V in. in medical schools and colleges. It is sufficiently powerful
to do all that is wanted in practical study, but necessarily in
research work a T V in. of wider aperture is required. For a
student it will be especially valuable, for it has of course more
working distance and a larger field than a T V in.

Another very important point is that, because of its great
working distance, it does not pick up by capillary attraction an
unfixed cover-glass. This is a source of great trouble when
working with a - in.

Zeiss supply a funnel for reducing the aperture of this objec-
tive, so that a dark ground may be obtained with an ordinary
dry condenser and a stop. Of course with an oil-immersion
condenser no funnel is required.

Henceforth, for research work, a perfect battery will consist of
a 2 in., 1 in., | in., ^ in., this iin., and a T V in. oil-immersion.

AND A NEW METHOD OF ILLUMINATION. 365

In the Navy, when Dreadnoughts were introduced, old-fashioned
battleships were scrapped ; so also in microscopical affairs those
who are wise will scrap all their dry lenses of powers higher than
3 in. or ^ in.

One can foresee that the advent of this new lens means much,
for just as oil-immersions have eclipsed water-immersions, so will
this new lens supersede the wide-angled dry lens, which cannot
compete with it in working distance, quality, field, or price.

It is to be hoped that Zeiss will issue an objective of this class
for the long as well as for the short tube. The most notable
feature in this new object glass is the near approach that has
been made towards apochromatism without the use of fluorspar.

There is, however, another matter for your notice viz. an
entirely new way of using an object glass for diatom or other

a

Fig. 1.

resolutions, a method, moreover, for which this new object glass
is peculiarly suited. The method is so simple that it can be
explained in a few words : (1) Place the diatom so that the striae
to be resolved are vertical in the field. (2) Set up a critical
imawe with the edge of the flame in focus and central to the
field, and open the diaphragm to its full extent. (3) By means
of the substage centring screws move the condenser so that the
image of the flame lies just outside the field of a high-power
eye- piece (fig. 1). If the striae are within the grip of the object
glass they will be resolved.

It just amounts to this, that if one is working at diatoms
with critical illumination and has need to resolve one, all that is
necessary is to move the side way adjusting screw of the substage
and place the flame image just outside the field, and the thing is
done in an instant, without any trouble with stops, slots, or
other apparatus.

You will notice that the amount of the displacement of the
condenser is very small (say twice the length of a Kavicida rhom-

366 E. M. NELSON ON A NEW OBJECT GLASS BY ZEISS.

boides), so that this new kind of illumination must not be
confused with that from a condenser considerably decentred,
with the illuminant so placed that the light passes through the
condenser obliquely, a form of illumination old and well known,
or rather which used to be well known.

Although there is no difficulty in executing the necessary
manipulation, the explanation of how the result is obtained is not
so easy. First, no direct light from the flame enters the field, but
it must be remembered that it is not a dark-ground image we are
dealing with ; for if it were high resolution would fail, as Mr.
W. B. Stokes has pointed out. The field is not dark, neither is it
light, but it is a sort of glow ; from whence does this glow come ?
At first it was thought that it must arise from internal reflections
in the front lens of the object glass, and that the lens was acting

Fig. 2. Fig.

3.

as its own lieberkiihn, as in fig. 2. But further experiments have
proved that this is not the case ; no doubt some light may travel
in that manner, but the amount that does so is quite small, and
wholly insufficient for the purpose. The main body of this light
is present owing to spherical aberration in the condenser, which
gives rise to a very oblique beam, as in fig. 3. For this kind of
illumination therefore a condenser with spherical aberration is to
be preferred to one more aplanatic.

There can be no question about extraneous light from the
illuminant having anything to do with it, for when a metal
screen, with a slit the size of the edge of the flame, was placed
close to the chimney, no difference in the effect was observed.

This kind of illumination will be of service, for it will enable an
observer to obtain high resolution with a dry condenser, in an
instant, without the troublesome manipulations usually necessary.

Journ. Quekett Microscopical Club, 8a: 2, Vol. XII., No. 7", November 1914.

307

A NEW LOW-POWER CONDENSER.

By Edward M. Nelson, FJR.M.S.
{Read April 28a, 1914).

Fig. 4.

Some time ago 1 pointed out to the Club that microscopists were
badly off for a low-power condenser, for, so far as I know, there
is no such appliance to be had. Mr. Curties kindly exhibits-
to-night one he has made from my formula. This condenser is
designed as a low-power illuminator, and not at all for the
purpose of resolving fine diatom striae. With the top on, its
focus is 1 inch, and with the top off 2 inches.* Both the lenses
are achromatised, and it will be seen that it is particularly
achromatic, as well as aplanatic ; it will work from the lowest
powers up to a | inch.

The first object I examined with it was a Navicula lyra, with
a Zeiss 12 mm. apochromat. I have been working with the
microscope now upwards of forty years, and never before have I
seen such a perfect image of this diatom. In general work,
with the lower powers, the flat of the flame of a reading
lamp is focused upon the object ; this with the 2 inch condenser
covers a large portion of the field, even of the lowest powers. It
will give an excellent dark-ground for pond life, etc., up to say a
| inch objective. This condenser is to be named " Quekett,"
after that illustrious microscopist.

Speaking of dark backgrounds, there is a great defect in many
condensers, viz. that the spot is not centred to the optic axis of
the condenser, because the cell holding the stops is not placed
accurately on the mount. This is a serious defect, because if the
stop is not centred, the microscopist is forced to use a much larger

* This back lens of 2-inch focus when used by itself in a holder forms
the best "verant" I have seen. It is very useful for the examination
of large microscopical objects, as well as of flowers, engravings, coin-,
postage stamps, seals, etc.

368

E. M. NELSON ON A NEW LOW-POWER CONDENSER.

stop than is necessary.* How often one sees a dimly lighted
object, with a halo of bright fog, on one side of the field, owing
to the use of an excentric stop larger than is necessary.

To remedy this defect, Mr. Curties shows a simple centring
stop-holder made from my design. The stop consists of a disc
with a hole in it which fits on a pin B ; this I designed for my
Jubilee microscope, which was made by Powell and exhibited at
the Club in 1887.

Why microscopists will have their stops cut out of the sheet, a
much more expensive plan than a disc fitting on a pin on a spider,

ZI

v

Fig. 4.

A, lever ; B. flat tube with the stop on pin ; C shows the flat tube placed
on the lever, with screw for fixing the appliance beneath the iris-box.

I am unable to tell you. But to return, this pin is fixed to the
end of a flat tube B, which slides on a flat bar A ; this forms the
centring adjustment right and left. The centring adjustment
rectangular to this is in arc, by moving the arm C, which is
pivoted below the iris box.

* If, for example, a centred stop of -4-inch diameter is requisite, and
supposing that the stop carrier is 1 inch out of centre, then a stop of
6 inch will be required to do the same work as the stop of *4 inch. Now
the area of a circle of "6 inch diameter is more than double that of a circle
4 inch diameter ; this shows the great loss of light an excentric stop-holder
causes.

Journ. Quek-ett Microscopical Club, Scr. 2, Vol. XII. , No. 75, November 1914.

369

BINOCULAR MICROSCOPES.

By Edward M. Nelson, F.R.M.S.
(Bead. May 2tth, 1914.)

Fig. 5.

In recent years several binoculars have been introduced ; none
of them, however, can be called new. The first, the Greenough,
by Zeiss * in 1897 was a twin microscope, a form of binocular
invented by Pere Cherubin d'Orleans nearly three hundred years
ago. The second, by F. E. Ives in 1902,f is very similar to one
designed by Wenham in 1866 as a counterblast to Powell's
high -power binocular in which the whole beam is sent into
each eye. % The third is a modification of the second by Messrs.
Leitz, and the fourth, by Messrs. Beck, is very similar to that
of Ives.

Before proceeding, let us enumerate the points gained by
binocular vision. They are four in number and were stated
by me in the English Mechanic || as follows :

1. Stereoscopism, or the power of appreciating solidity.

2. Increase of apparent magnifying power.

3. Increase of illumination.

4. Increase of colour perception.

The first binocular we have to deal with, viz. the Greenough
twin microscope, became a practical form owing to the re-
introduction of the Porro prism by C. D. Ahrens in 1888.
Obviously, it can only be used with very low powers, but never-
theless I have had no reason to alter the favourable opinion
I expressed for this form of binocular when it was first ex-
hibited by Messrs. Zeiss. In this instrument all the above

* Journ. B.M.S., 1897, pp. 599-600.
t Ibid., 1903, p. 85, Fig. 3.

X I am indebted to Mr. Rousselet for kindly bringing the Ives binocular
to my notice.

Journ. B.M.S., 1914, p. 5.
|| 1911, Vol. 94, No. 2432.

370 E. M. NELSON ON BINOCULAR MICROSCOPES.

four attributes of binocular vision are secured. In tins micro-
scops the left-hand view of the objective is sent into the left
eye, and the right-hand view into the right eye; this, because
of the erection of the image, gives an ortho-stereoscopic image.
If the microscope had been of the ordinary inverting type the
image would have been pseudo-stereoscopic. It was due to
ignorance of this principle that several of the early bino-
culars were pseudo-stereoscopes. One of the most important
points in this, as well as in all forms of binoculars, is that
the images should be accurately superimposed. Several tests
have been proposed ; one was that an object should be
placed upon the stage, so that it should just touch, say, the
right edge of the field of the right-hand eye-piece. This eye-
piece is then transferred to the left-hand tube, and if the object
still touches the same portion of the field with the same eye-
piece the adjustment was supposed to be correct. But this
is no test at all, for it tells you nothing about the really
important question, which is whether the discs of the fields
are themselves superimposed.

The best test for a Greenough is to oscillate rapidly a strip
of card half-inch wide before the fronts of the objectives. If
the images shake, then they are not accurately superimposed,
and the objectives require readjusting in their seats.

Leaving now the twin microscope, we will pass on to the
other kind of binocular, which has only one objective. In the
Wenham this important adjustment is performed by the align-
ment of the tubes, for the tilt of the prism has very little
effect, but its edge must be carefully set at right angles to
a line joining the centres of the eye-pieces.

The single objective binocular may be divided into two kinds,
viz. those of the Wenham or Stephenson type, which split the
beam at the back of the objective, and those of the Fowell type,
which pass the whole beam. All those of the Wenham type
possess the first of the attributes enumerated above, viz. stereo-
scopic effect, for in an ordinary inverting microscope, at the
left-hand eye-piece the Ramsden disc will be a miniature of
a cross-section of the beam issuing from the right-hand half
of the objective, and that at the right-hand eye-piece from the
left-hand half of the objective, the inversion of the image
necessitating a cross-over of the pencils, for if there were no

E. M. NELSON ON BINOCULAR MICROSCOPES. 371

cross-over the image would be pseudo- stereoscopic. There is
no cross-over in a Stephenson, but then it is an erecting
microscope.

The binocular of the Powell type, which passes the whole
pencil, does not possess the first attribute of stereoscopism : the
image in both eyes being identically the same. No doubt,
owing to the employment of both eyes and for physiological
reasons, there may be more or less of a stereoscopic effect, but
that is an entirely different thing from true stereoscopism.
When, for example, the full moon is observed through a field-
glass it appears as spherical as a cricket-ball, the images in
each eye must be identical and no true stereoscopism can be
present.

If half the Kamsden's disc above the eye-lens is stopped out
by a diaphragm, so long as the cross-over is preserved, the
image in an inverting microscope will be ortho-stereoscopic. This
was mentioned by "Wenham in 1854; and later, in 1882, Dr.
Mercer pointed out that a diaphragm is not needed, but an
ortho-stereoscopic effect may be obtained by making the inter-
ocular distance less than the interpupillary, which causes the
iris of the pupil of the eye to cut off the inner half of the
Ramsden disc.

The disadvantage of a diaphragm above the eye-piece is that
it occupies the same place as that in which the eye ought to be;
and the disadvantage of Dr. Mercer's method is that the head
and eyes must be kept absolutely steady, otherwise there will be
a flickering of the image, which causes strain and distress to
the eyes : the higher the power, the smaller the Kamsden disc
and the greater will be the flickering and strain and fatigue
to the eyes. For these causes ortho-stereoscopism in a binocular
of the Powell type is of a different character from that of the
Wenham or Stephenson type. In books dealing with this
subject the Wenham super-eye-piece diaphragm and the Mercer
narrow inter-ocular distance are treated as alternative plans,
equal in efficiency to the Wenham divided objective method.
Such, however, is not the case. It is only necessary to place
two microscopes alongside each other, charged with similar
objectives and powers, one having a Wenham divided objective
and the other a Mercer narrowed inter-ocular distance, when
an examination of the same object will at once dispel any theory

372 E. M. NELSON ON BINOCULAR MICROSCOPES.

as to the equality of the results, the ortho-stereoscopism in
the Wenham being superior to that in the other.

In the Wenham and Stephenson, ortho-stereoscopism is weak
with objectives which have less than 20 of angular aperture (say
1^ inch of *17 N.A.), and the divided objective breaks down with
high powers. A divided objective binocular may be said to be at
its best with a \ inch ; good with 1 inch, |, T 4 (j-, and g ; fair with \ ;
but failing with a 4. Very small Wenham prisms have been
made and mounted on a funnel and placed in the mounts of a
Y2- ', the result being so indifferent that further experiments
in that direction were abandoned.

The Wenham plan possesses a great advantage over all other
kinds of stereoscopic binoculars, viz. that the straight tube is
free from glasses, prisms, or other appliances likely to disturb the
image. You will naturally ask, Why then was -the Powell non-
stereoscopic system introduced ? The answer is that it was
intended to come in where the W'enham left off, for Powell
engraved on his Wenham prism, " For Low Powers," and on his
own prism, " For High Powers." The reason why the high-power
prism fell into disuse was on account of the poor definition that
could be obtained with it. It bad no clear tube like the Wenham,
and it should be remembered that prisms and flat glass surfaces,
owing to the manufacture of prism field-glasses, are now made
with a precision and accuracy altogether unknown in 1865, when
Powell made his.

Binoculars of the Wenham or divided lens type have the dis-
advantage of indifferent definition of objects placed vertically
in the field. If, for example, that well-known test for medium
powers, the hair of the Polyxenus lagurus, be placed vertically in
the Wenham, with, say, a one-third objective, the definition
will be fuzzy ; but directly the hair is placed horizontally in the
field, the image becomes sharp. In ordinary work with a
Wenham, where an ortho-stereoscopic image is of primary im-
portance, this defect is not noticed, and probably only a few
raicroscopists are acquainted with it. But with the Powell type
of binocular, this error does not exist. The image is the same
in all azimuths. Now, in the Wenham high-power binocular,
which was introduced in reply to Powell's, the beam was divided
by two right-angled prisms with an air-space between tbem, the
inclination of the surfaces being adjusted near to the critical

E. M. NELSON ON BINOCULAR MICROSCOPES. 373

angle so that some of the light was passed while some was
reflected. As this took place at both surfaces a double image
was made in one tube, which, of course, was fatal to the design,
and the binocular never came into use. Prof. Abbe's binocular
eye-piece was made on a similar plan and failed for the same
reason. Subsequently, however, a method was discovered for
depositing a semi-translucent film of silver on glass, by which
means a beam could be half reflected and half transmitted. This
method was adopted by Ives, and the doubling of the image in the
one tube was avoided. The Ives binocular resembled the Wenham,
inasmuch as the prism could be withdrawn and the instrument
used as a monocular. But it also differed from it, for in the
Wenham the inter-ocular distance was adjusted by lengthening
or shortening the draw-tubes, while in the Ives it was accom-
plished by a lateral displacement of the side tube in arc, the
lower end of this tube being pivoted on a hinge. This was
a good design, for it permitted the inter-ocular distance to be
adjusted without disturbing the tube length. In 1860, when the
Wenham was first introduced, low powers, with their double
fronts, were very insensible to alteration of tube length, and as
all powers higher than a | had correction collars, any alteration
of tube length was of no moment ; this, however, no longer
applies, because objectives now made with single fronts having
over-corrected backs are very sensitive to tube length. So in
designing a binocular for use with such objectives, particular
attention must be given to tube-length adjustment.

Now, lately, Messrs. Leitz have brought out a new binocular of
the Powell type ; the arrangement of the prisms, which deflect the
rays right and left, differs from the many kinds that have been
invented for this purpose. The semi- translucent silver film
method has been adopted by Messrs. Leitz in their new binocular,
and an almost equally illuminated image is seen in each tube.
By means of their very perfect system of working prisms they
have secured a really sharp critical image in each tube. The
tubes are parallel to one another, but the instrument cannot be
used as a monocular, for neither body is in the optic axis of the
objective. Messrs. Beck have also brought out a binocular
microscope with the two Ives prisms joined in one. The bodies
are converging, but as one body is in the optic axis of the
instrument, it can be used as a monocular.

374 E. M. NELSON ON BINOCULAR MICROSCOPES.

A great deal has been made of the difference between parallel
and converging tubes. It has been urged that parallel tubes are
conducive of eye strain and fatigue. Having now had a Leitz
microscope in constant use for nearly three months, and having
done prolonged work with it, no more eye-strain has been found
with the parallel tubes than with a Wenham, and with both
there is less fatigue than with a monocular.

To me the image plane in a microscope appears at so definite
a distance that I seem able to hold a pencil in front of it, or
behind it, or touching it. When using a binocular I simply look
at the image in this plane, being quite as unconscious of either
the parallelism or convergence of the eyes as if I were looking at
various objects in the room, or on the table. During the course
of these experiments several curious observations were made.
Various persons were asked to examine the images in the Wenham
and in the Leitz for the purpose of ascertaining their opinion as

W M

Fig. 5,

to the relative amount of stereoscopic effect in each. Two persons
having good normal vision saw no stereoscopic effect in either,
the images in both instruments appearing quite flat ; one of them
could see no stereoscopic effect either in an ordinary stereoscope
or in a field glass. Two others saw stereoscopism in the Wenham,
but not in the Leitz with the Mercer method. With the same
object and same power in both (| inch and B eye-piece), most
persons said that stereoscopism was stronger in the Wenham,
owing probably to want of practice and experience with the
Mercer method.

When the inter-ocular distance in the new binocular is kept
of the same width as the inter-pupillary, the microscope is a
non-stereoscopic binocular. The Mercer plan of reducing the
inter-ocular distance is found to produce fatigue on account of
the flickering of the image when the Ramsden disc is small.

Figure 5 shows the reason why eye strain and fatigue,
which are present with the Mercer method, are absent with

E. M. NELSON ON BINOCULAR MICROSCOPES. 375

the Wenhani ; the circles in W and M represent the pupil of
the eye, the semi-circle in W is the Ramsden disc in a Wenham,
and the portion of the circle in M is the Ramsden disc when
the inter-ocular distance is less than the inter-pupillary in the
Mercer method. It can at once be seen that a slight movement
of the head will not affect the luminosity in W, but in M the
head cannot be moved in the slightest degree without either
increasing or diminishing the amount of the Ramsden disc
cut off by the iris of the pupil ; necessarily, therefore, if in one
eye the Ramsden disc is enlarged it is cut off in the other eye,
and vice versa, which is the cause of the nickering previously
mentioned. A moment's consideration will show how this defect
in the Mercer method may to a certain extent be minimised.
Obviously the larger the Ramsden disc the less noticeable will be
this defect. This, of course, points to the use of a low-power
eye-piece with any given objective. The low-power eye -piece
has an additional advantage -viz. that the rays emerge at a
smaller angle than in the case of a deep eye-piece, and this
permits the eye being held at a little distance from the proper
eye-point, where the Ramsden disc is expanded. Hence the
rule for stereoscopism with the new binocular is to make the
inter-ocular distance somewhat less than the inter-pupillary, and
not to use eye-pieces deeper than 1| inches, and to hold the eye
a little way behind the eye-point.

There are two other sources of eye strain and fatigue common
to all binoculars of whatever type : the first is non -coincidence
of the superimposed fields. This by no means uncommon fault
is due to carelessness in fitting and putting together ; it is a
source of great eye strain and fatigue, and the purchaser of a
binocular microscope should be particular to see that the fields
are precisely superimposed. The second is a difference of foci
in the tubes. In the binoculars both of Messrs. Leitz and Beck
provision is made for this by a focusing arrangement in one of
the eye-tubes. In the Greenough it is accomplished by means
of a focusing adjustment in one of the objectives. If, therefore,
a microscope is provided with some such arrangement, the user
need not be troubled about this point.

Passing on now to the second attribute of a binocular viz.
that of increased apparent magnifying power, it is found to be
as obvious in a microscope as it is in a field glass. Its precise

376 E. M. NELSON ON BINOCULAR MICROSCOPES.

amount is difficult to determine, nor is it known if it is the
same for all persons. As I pointed out elsewhere, it is inaccurate
to say that there is an increase of apparent magnification in a
binocular ; what really takes place is that in a monocular there
is a diminution of apparent magnifying power, and that this dimi-
nution is non-existent in a binocular. If any one examines a
lighthouse, a ship, or other object with a 2 or 3 power monocular
telescope, the image appears no larger than when it is seen with
the naked eye. The image, as any one will tell you, is brighter
and clearer, but not larger. Directly the image seen in the
telescope is superimposed on that seen with the other eye the
magnification of the monocular is demonstrated, which generally
causes surprise. Having given this subject considerable attention,
I am of opinion that the true magnification is seen in a binocular,
but that with a monocular, either telescope or microscope, this
is reduced.

The third attribute viz. illumination : It is doubtful if there
is much gain in the Greenough type of binocular, as the amount
gained by the use of both eyes is probably lost owing to
the prisms, surface reflections, etc. Of course, with a single
objective type of instrument there must be a loss. This is of
no importance, for in a microscope one has usually more light
than is needed.

The fourth attribute : Experiments have shown that colour
tints are increased in a binocular ; this is a distinct gain, for
there is always much and often total loss of colour in micro-
scopical observations.

There is another form of binocular which must be mentioned,
viz. the binocular eye-piece. This was an early invention of
Wenham ; the next to take it up was Tolles, of Boston, U.S.A.,
who made a very good one by using prisms on the Nachet
plan, dividing the beam by means of an isosceles prism. Tolles'
binocular was well made, stood deep eye-pieces, and had the
advantage that both tubes were similar ; consequently the illumi-
nation and path of the rays was equal in each. The advantage
this system possesses is that it permits of objective correction by
draw tube. With other binoculars objective correction is not so
easily accomplished.

The last form of binocular eye-piece was brought out by
Professor Abbe. This, as we have seen above, was a failure.

E. If. NELSON ON BINOCULAR MICROSCOPES. 377

There was another objection, viz. that the path of the rays was
much longer in one tube than in the other, so that two different
forms of eye-pieces had to be used. Very few were made, and
it is probable that no more will be.

In conclusion let us examine the position of these new
binoculars. From what has been said above they are clearly a
class by themselves. It would be quite inaccurate to entertain
the idea that these instruments are a new kind of stereoscopic
binocular constructed to enter into competition with, and finally
to supersede, the existing binoculars of the Wenham and
Stephenson types ; for from what we have seen they only possess
the first attribute, viz. stereoscopism in a limited manner. The
word "limited" is used in default of a better expression. It
does not mean that with the Mercer effect stereoscopism becomes
less strong, for, on the contrary, with the Mercer effect hyper-
stereoscopism is often present, and care should always be taken
to guard against it. With the Mercer effect a cell, for example,
which is, and which under a Wenham would look, like an
ellipsoidal football will appear under a hyper-stereoscopic Mercer
effect as if standing on end.

The centre of that beautiful diatom, plentiful on " Mud
Cuxhaven " slides, viz. Actinocyclus Ralfsii, under hyper-stereo-
scopism appears at the bottom of a deep pit, the outer annulus
being highly raised,* whereas we know that the structure is a
kind of shallow saucer. The word "limited" is intended to
apply to the stereoscopic condition that the Itamsden disc cannot
be centred to the pupil. The Mercer plan also entails loss of
light and of resolution of vertical striae. Messrs. Leitz provide
their inter-ocular adjustment with a millimetre scale. The
observer should carefully note the precise adjustment that will
centre the Ramsden disc to his own eyes ; half a division on the
scale (which represents 1 mm.) or even less ought to suffice for
the Mercer effect. The test of coincidence of the inter-ocular
with the inter-pupillary distance is that of maximum brightness.
Luminosity quickly falls off with either increase or decrease of
inter-ocular distance. With a little practice, one becomes so
expert in judging the luminosity that a reference to the divided
scale is seldom necessary.

* Seen best with transmitted light, a No. i objective and a 1 inch
eye-piece.

378 E. M. NELSON ON BINOCULAR MICROSCOPES.

You will then naturally ask, If these new binoculars are not
stereoscopic, what is their use? Their use is confined to the
employment of full Kamsden discs in each eye, that is for
work with non-stereoscopic images. An enormous amount of
microscopic work is done with images of that kind, and when
prolonged work is undertaken with the new binocular great
relief and comfort to the eyes will be secured. But to say, on
the one hand, that one of these instruments when used for,
say, the examination of pond life with a \ inch and the Mercer
effect is going to supersede a Wenham, and on the other hand
to state that by means of this new binocular delicate secondary
structures on diatoms will be more easily seen than with a
monocular, is to talk nonsense. At the upper limit they cannot
compete with the monocular, and at the lowest limit they cannot
compete with the Wenham ; but in their own sphere they are
extremely useful and form a very important addition to the
modern improvements in Microscopy.

At any time with the new binocular the Mercer effect can be
turned on to determine the relation of the various parts of an
object ; but it must be borne in mind that stereoscopism in a
microscope with the higher powers is only partial, and whether
it is present or not depends largely upon the nature of the
object; for example, with a medium power, such as \ or a
i, the rays of a Heliopelta will exhibit strong stereoscopism,
but many other objects with the same power will show none.
With a \ and a spread slide of P. angulatum, it is difficult to
determine whether a valve is convex or concave side up. Stereo-
scopism in macroscopic vision differs from that in microscopic
vision inasmuch as it is influenced greatly by the thickness of
the object.

With macroscopic vision stereoscopism is seen equally well
with either a book or a bookcase, but that is not so with
microscopic vision. In that case stereoscopism would be present
with our allegorical bookcase but not with the book. Low
powers deal with thick, coarse objects, and therefore stereoscopism
is present ; but with the higher powers it is necessary to select
suitable objects for the demonstration of the stereoscopic effect.
For instance, bacteria dried on cover do not exhibit any more
stereoscopism with the new binocular than with a monocular,
for in a monocular they can be made to look like sausages ; but

E. M. NELSON ON BINOCULAR MICROSCOPES. 379

when bacilli in tissue are examined with the Leitz binocular, a
^ and the Mercer method, a beautiful picture of them in
perspective projection will be seen as well as of the cell nuclei
which appear spherical as marbles.

It is a good plan when working with this new binocular to
turn on the Mercer effect and when the form of the image has
been mentally grasped to turn it either wholly or partly off,
for when the stereoscopic form of an object has once been
realised by the mind re can be retained, although the optical
conditions which gave rise to it have been removed. Some will
have noticed, when looking at parquetry representing cubes, that
if the effect when first noticed is intaglio it is a matter of some
difficulty to reverse this mental image so that the cubes shall
appear to be in alto-rilievo.

I asked Messrs. Leitz to make me a couple of tubes to slide
over their tubes, by which means tube-length adjustment can
be accomplished. The tubes can be drawn up and down over
the fixed tubes and the eye-pieces also can be partially drawn
out, as the tubes are sprung both top and bottom. Without
these tubes it was not possible to obtain a critical image with
Messrs. Leitz' own objectives for the Continental short tube.

The great charm in these new binoculars consists in the
sharpness of the image combined with ease and comfort of vision,
hence the need for lens correction either by alteration of tube
or by screw collar. The sharpness of image in my instrument
at least is very little behind that of a monocular, for it requires
a delicate test to perceive any difference at all, and often a pair
of 18 compensating eye-pieces have been used with advantage.

With a ^ inch objective and upwards, these new binoculars
have the field all to themselves, as no other binocular for sharp-
ness and crispness of image can for a moment compete with
them. With low powers and 1^ inch eye-pieces and a slight
Mercer effect they give lovely images, but, as was hinted above,
with the Mercer effect one must alwaj^s be on one's guard against
hyper-stereoscopism. Recently a shock was experienced on finding
that a Radiolarian which appeared under the Mercer effect as
round as an orange, when viewed on edge was shaped rather like
a mince pie. Here the Wenham gave the truer image.

Latterry, even the Greenough, which is known to give beautiful
images, has been suspected of hyper-stereoscopic tendencies.

Journ. Q. M. C, Series II. No. 75. 27

380 E. M. NELSON ON BINOCULAR MICROSCOPES.

I never expected to live to see a critical image of a Podura
scale in a binocular, but that is now an accomplished fact, for I
have seen a most beautiful picture of a Podura scale with the
Leitz binocular and an apo 4 mm., and that, too, critical in all
azimuths.

Dark-ground images are very suitable for the new binoculars
because the objective is working at full cone, so there is a larger
Ramsden disc than would be usually the case with transmitted
light.

Messrs. Leitz sent with the microscope some of their new
Orthoskop-Kellner eye-pieces, the performance of which is very
satisfactory. I have had a cap, attachable to the eye-piece by a
small screw, made to prevent the eye lens being smeared by
contact with the eye-ball. This with a binocular happens
frequently, so that a process of continual wiping of the eye-lens
is necessary, which causes interruption and much interference
with one's work.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 75, November 1914.

38]

NOTES ON THE CULTIVATION OF PLASMODIA OF

BAD HAM I A UTRICULARIS.

By A. E. Hilton.

{Head May 26*A, 1914.)

Fig. 6.

A free-flowing mass of naked and almost undifferentiated
protoplasm, such as we have in the plasmodium of Badhamia
utricularis, suggests opportunities for biological experiments,
with unusual promise of success. From living matter in so
primitive a condition, it should be possible, one imagines, to gain
a more intimate knowledge of the fundamental substance which
is the basis of all physical life.

Systematic investigations, however, depend upon a constant
supply of material, and a continuous supply of plasmodia is not
easy to obtain. In natural surroundings, they are only to be
found when conditions of temperature and moisture are suitable ;
and even then, in most districts, they are very scarce. More-
over, the removal of a plasmodium to a place suitable for
studying it, generally results in the plasmodium shortly passing
into the sporangial stage, or perishing from lack of proper
nutriment. Either way, the immediate end is defeated.

In the Introduction to Mr. Lister's Monograph of the
Mycetozoa, recently revised by his daughter, it is stated that
" The plasmodium of Badhamia utricularis is one of the very few
we are acquainted with that feed on living fungi," and that " it
is capable of being cultivated without limit on Stereum hirsutum
and allied species, and can be observed under the microscope to
dissolve fungus hyphae as the hyaline border of a wave of the
yellow plasmodium advances over them." In many places,
however, an unfailing stock of the fungus mentioned is difficult
to ensure ; so that here, again, a difficulty arises.

382 A. E. HILTON ON NOTES ON THE CULTIVATION OF

Professor De Bary (1884), in his great work on the Com-
parative Morphology and Biology of the Fungi, Mycetozoa and
Bacteria, mentions boiled cabbage leaves as having been used for
the cultivation of Mycetozoa ; but he does not name the species
which were cultivated, and boiled cabbage leaves, if kept for any
length of time, become too offensive for endurance.

In 1906, an account was published in Germany of experiments
in the cultivation of plasmodia made by J. G. Constantineau ;
and these are alluded to both in Mr. Lister's Monograph and
the Royal Microscopical Society's Journal for April 1907. In
neither of these are details given, or any indication of the
extent to which the experiments were successful. Possibly
they were too technical to be of general use. '

No apology, therefore, is needed for placing on record the
result of experiments made during the last few months, which
suggest a method of continuous cultivation of plasmodia of
Badhamia utricularis, at once simple and practicable. Whether
this method, with or without modification, is applicable to
plasmodia of other species, I have not had an opportunity of
<letermining. Other workers may perhaps take up the suggestion
and carry the matter further.

In the first place, I have found that the growth of a Plas-
modium of B. utricularis can be stimulated by the occasional
application of a mixture of ammonium phosphate * and cane
sugar, half an ounce of the phosphate and the same weight of
sugar being dissolved in a quart of water.

In the second place, I find that the plasmodium will feed and
grow on bread kept moistened with water, especially if some of
the mixture described be added to it from time to time.

The effect of the mixture seems to be both direct and indirect-
It appears to impart greater vigour to the plasmodium, so
increasing its feeding capacity ; and it also benefits the plas-

* Since the above paper was read, Mr. James Grundy has informed mc
be has added calcium phosphate to the mixture with excellent results.

PLASMODIA OF BADI1AMIA UTRICULARIS. 383

m odium indirectly by promoting the growth of filamentous
moulds, such as Aspergillus or Penicillium, which soon appear on
fungus or bread, after the mixture has been applied to it. The
hyphae of these moulds are dissolved and absorbed by the proto-
plasm as food.

In using the mixture discretion must be exercised, according to
the condition of the plasmodium, as sometimes plain water is
preferable ; but the careful observer will find sufficient indications
to guide him in this respect. No precise rules can be laid down,
but the student will find that with these auxiliary helps he will
be less dependent than heretofore on a supply of Stereum or
similar fungus, although it may be advisable to use some of that
at times, if convenient, as being the more natural food. Any
fungus which becomes putrid must be removed, or it may poison
the plasmodium ; but the bread is not so liable to become
injurious, and may remain a reservoir of protoplasm until, after
a prolonged period, the plasmodium has eaten it all.

]STote. I have also been asked to describe, for the benefit of
our readers, my method of exhibiting the reversing currents of
streaming plasmodia, a description of which has been given in
the Journal.* The very simple arrangement is shown in the
diagram below.

Fig. 6.

A tube of this size is sufficient, and a ring of blotting-paper,
with sclerotium upon it, is placed inside ; the sclerotium being
between the paper and the glass. A few drops of water are
added, the cork is inserted, and the tube is then tilted and
revolved until the water has soaked the paper and moistened the

* Joum. Q.M.C., Vol. X., pp. 263-270, November 1908.

384 A. E. HILTON ON PLASMODIA OF BADHAMIA UTRICULARIS.

whole of the interior surface of the tube. A small hole is bored
through the cork to admit air without allowing too much
evaporation ; or the cork may occasionally be removed. If
necessary, a drop or two of water can be added now and then, to
keep the air moist. Only plain water should be used. When
the sclerotium revives, the plasmodium creeps on to the glass on
either side of the ring of paper, and the reversing currents can
then be seen by placing the tube on the stage of the microscope
and throwing the light up through it from the mirror beneath.
A 1 inch objective, focused on the veins of the spreading
plasmodium, shows the streaming movements quite plainly. The
sclerotium should be placed in the tube the day before the
plasmodium is required for exhibition.

Joarn. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 75, November 1014.

on K

85

ON THE MINIMUM VISIBLE.

By A. A. C. Eliot Merlin, F.R.M.S.

(Read October 27th, 1914.)

I have read with great interest and profit our President's
Address on " Organisms and Origins." The subject is one that
must fascinate every microscopist, whatever his line of research
may be. In the address a point was raised respecting the
minimum visible, it being stated that " it seems impossible to
obtain any precise information as to the size of the smallest
particles that can be seen with the microscope."

Now, setting aside the ultra-microscope, as our knowledge is
very exact and definite indeed on this subject, it may prove of
interest to deal with the question at some length. As a matter
of fact, when a particle properly illuminated is just visible under
a given objective, if the aperture be cut down by means of an iris
diaphragm placed above the back lens so that the particle just
ceases to be visible, and the numerical aperture to which the
objective has been thus reduced is measured, then the dimensions
of the particle can be exactly ascertained from the antipoint table
published by Mr. Nelson in the Journal of the Royal Microscopical
Society. This antipoint table should prove invaluable when
accurate and minute measurements are necessary, but little
interest has been apparently evinced in the matter since micro-
metry of a high order is no longer practised, in England at least.
Leaving this for the present, I venture to refer to and examine
the claim made by Mr. Brown at a recent meeting of the Club
that he had seen central " pores " on the surface of the frustules
of certain diatoms ; which he estimated at l/200,000th of an inch
in diameter. On reading Mr. Brown's " Notes on the Structure
of Diatoms," * I examined a specimen of Pleurosigma balticum,

* Journ. Q.M.C., Ser. 2, Vol. II. p. 317.

386 A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE

in realgar, under a very perfect recent 1/1 2th apochromat of
N.A. 1*4, employed with a magnification of 4,200. Mr. Brown's
central "pores" could be readily distinguished at a certain high
focus on the outer layer of the valve. But in the " pores " so
revealed I immediately recognised my old friends Dr. Boyston-
Pigott's " dark eidolic dots of interference." In thus frankly
stating my conviction, I am sure that Mr. Brown, as a veteran
observer, would wish me to pursue no other course. We are all
liable to make mistakes in the interpretation of diatomic struc-
ture, and the only hope of progress lies in friendly criticism and
the exchange of views. Although I consider Mr. Brown's central
" pores " of Pleurosigma balticum, Navicula serians and P. angu-
lation! to be clearly false ghosts, it is by no means unlikely that
the outer layers of these diatoms may be perforated with fine
secondary structure, like the forms with coarser primaries.
Under the most critical conditions, with T4 N.A. and a magnifi-
cation of 4,200, something of the kind has been seen both in
P. balticum and N. serians. These appearances, however, are
far more elusive and difficult than the eidolic central clots, and
quite different in aspect and position. So far as my experience
goes, capped diatomic primaries are always pierced by at least
three or four secondaries when any such structure is observable.
It may nevertheless be safely asserted that if the primaries of
P. angulatum are thus capped and pierced, the secondaries must
be as much beyond the grasp of our best lenses as are the eidolic
dots of A . pellucida.

In order to show how similar are the observational conditions
described by Dr. Royston-Pigott as necessary for the proper
demonstration of eidolic clots to those specified by Mr. Brown
concerning his central diatomic " pores," I must quote Dr. Royston-
Pigott's remarks on the subject at some length. In "Micro-
scopical Advances " * it is stated : " With regard to attenuated
circles, nothing are more abundant in diatomic and scale
markings. If a spherule be l/60,000th of an inch, the black
marginal ring is generally about one-fifth of this, or 1 /300,000th
thick, ornamented with a minute central black clot. The clot and
its fellows are amongst the most interesting and surprising sights
in minute microscopy. Few glasses will show them. That a

* English Mechanic, vol. xlviii. p. 209.

A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE. 387

minute spherule should be capable of exhibiting the same
recherchcs phenomena as a delicate glass lens l/30th focus solely
from its refractions and chromatic aberrations, at first seems
quite incredible." In another place * Dr. Poyston-Pigott con-
tinues : " The existence of dark eidolic dots of interference is an
important fact which now requires further elucidation. Darkness
has resulted from excessive light. Wave neutralising wave, certain
undulations killed each other. This is seen on a grand scale in
the solar spectra formed by a small lens in the foci of a very fine
microscojDe. Forty-eight dark rings have been counted developed
by an extremely small solar beam. The feeble refractions occur-
ring in a diatomic convexity cannot develop a very numerous
retinue of rings ; but sufficient diatomic lenses have been accumu-
lated for the purpose indicated. To exhibit successfully a series
of eidolic dots of interference demands very careful illumination
and a very fine objective. Their size varies with the nature and
diameter of the refracting spherule. The 1/Sth water lens of
Powell and Lealand seems to excel all my others in detecting
them in different focal planes. Six have been in order thus seen,
but in small spherules such as those of P. angtdatum many dots
are too faint for recognition. My experience of scale molecules
has convinced me they also are wonderfully transparent, display
black marginal test rings, and often one eidolic dot." . . . " These
dots are well developed by large beading of diatoms from 1/9, 000th
to 1/1 4,000th of an inch in diameter. Extremely large spherical
beads are seen in Cresswellia superba and in Cestodiscus superbus
(beads 1/1 2,500th) ; E. costatus and C oscinodisens radiatus are
also fine examples. To exhibit successfully all the eidolic dots of
interference in successive focal planes demands very excellent
glasses, careful precautions, and, above all, well-separated diatomic
beads. They may be caught above very small diatomic and scale
beading. Remarkably good eyesight has distinguished them
above the bosses of P. angulation and occasionally I have
detected two sets of dots when one stratum of beading lies just
below another. In general, except in strongly pronounced
diatomic bosses, the observer may rest satisfied with finding the
primary eidolic dot, No. 1, fig. 1 in the diagram. f A better glass

* English Mechanic, vol. xlix. p. 315.

t A diagram showing a series of eight gradually diminishing dots is
annexed to the original paper.

388 A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE.

may enable him to detect Nos. 2 and 3 by daylight. Lamplight,
unless its yellow tint be subdued with a blue chimney and other
blue glasses, extinguishes the dot by the flame image produced by
the diatomic lens. It may be recovered, however, in front of it
by careful manipulation." ..." Dr. Van Heurck obligingly
photographed with the new apochromatic glass the eidolic dot
shown by the beading of P. angulatum."

Dr. Royston-Pigott estimates the dots in P. angulatum to be
attenuated to 1 /250,000th of an inch and considers that
extremely minute dots, about 1/300, 000th, are not only found
amongst diatoms, but reveal themselves in the transparent
headings of moth-scales, and adds, " but there are many forms
of these dots." It is also remarked that " exquisitely small and
black dots can often be seen in focal planes elevated slightly
above diatomic beads by using a black central stop below the
condenser. It requires very grand glasses to display these elegant
results." It is needless to point out that the late Dr. Royston-
Pigott was an upholder of the now abandoned view that the
perforations of diatoms were solid silex beads or bosses. The
foregoing sufficiently proves that the central eidolic dots or
" pores " of diatoms were well known twenty-six years ago, but
those specially interested in the subject should read the papers
referred to.

Setting aside all such diffraction phenomena, or false ghosts,
probably the most delicate, true diatomic structures just within
the grasp of our finest modern objectives of large aperture are
the thin perforated " veils "' to be detected on certain diatoms.
Of these perhaps one of the best examples is Triceratium america-
nitm, var., Oamaru, mounted in styrax by M oiler. It is a difficult
structure with axial screen illumination, but there can be little or
no doubt that the appearances observable represent real perfora-
tions in a thin outer plate. In this diatom there is no complicated
structure to bewilder the observer and manufacture false ghosts.
It is, however, extremely improbable that the minute perforations
of the IViceratium americanum, difficult as they are, represent
anything smaller than the 1/1 00,000th of an inch, and being
subject to the limitations of the laws of diffraction, like
all periodic structures, are consequently of little help as
an example of the minimum visible under more favourable
conditions.

A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE. 389

In biological investigations it is frequently required to view
widely scattered living particles, or germs, of various sizes down
to the most minute dot that can just be detected. When any
such particle is under observation nothing is easier than to
measure its dimensions accurately by the anti point method.
There is in my cabinet a section of fluor spar, given to me by
Mr. Traviss, which contains numerous liquid-filled cavities of
various sizes. In each cavity there is a rapidly moving bubble.
Some of these bubbles, under a 1/1 2th apochromat of 1*4KA.,
appear as mere trembling specks only just visible and within the
grip of the objective, and there are probably others too minute
to be seen at all. Selecting a bubble just visible under such
conditions when illuminated with a large axial cone and Gifford
screen, if we wish to ascertain its diameter we have only to refer
to Mr. Nelson's papers, "A Micrometric Correction for Minute
Objects," * and " The Influence of the Antipoint on the Micro-
scopic Image shown graphically." f These papers contain all
the necessary explanations and data, and we find from the
amended table in the latter paper that with a working aperture
of 1*4 and screen the minimum particle visible must have a
diameter of 0-00000265 (l/377,358th) in., or 0'0673 /x : the photo-
graphic limit being with similar aperture 0-00000209 (l/478,4:69th)
in., or 0'5031 /x.

Thus we can measure accurately the diameter of the smallest
particle or bubble visible with a given aperture. The accuracy
of the result depends on knowing exactly the N.A. employed at
extinction point, and this must in each case be found with an
accurate apertometer. It is advisable that the working aperture
should nearly equal the N.A. of the objective at the extinction
point, but it need not necessarily be quite full cone. When the
critical point is reached a very slight decrease of N.A. makes all
the difference between easy visibility and invisibility. Mr.
Nelson's first table " was computed by the formula

5-4686 \ W.A.
The numerical coefficient was determined from data found by the

* Journ. R.M.S., 1903, pp. 579-82.

t Ibid., 1904, pp. 269-71. See also " On the Measurement of Very-
Minute Microscopical Objects " {Journ. R.M.S., 1909, pp. 549-50).

390 A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE

extinction of the image of a minute point by reducing the W.A.
to 0'165. The size of the point was measured by a wide-angled
oil-immersion, and a W.A. of 0*9, and was found to be apparently
1/50, 050th inch. From this we have

6-6961X-165 = 50,050.
And

:0-000003663.

li-6961\-9

Employing this as a provisional correction, we find the size of the
point to be 1/4 2,396th in. Again, using this measurement, we
obtain a new numerical coefficient, viz. 5*6587, and finally find
the size of the point 1/40, 875th in., and the coefficient 5*4686 as
stated above. In this calculation A is the reciprocal of the wave-
length, or the number of waves per inch, given at the head of
each column in the table." In Mr. Nelson's subsequent paper,
" The Influence of the Antipoint on the Microscopical Image
shown graphically," the data will be found for the slightly
amended table given therein.

Shortly after the publication of Mr. Nelson's papers on this
interesting subject, Dr. Coles kindly sent me a well-stained
balsamed slide of the putrefactive microbe B. termo. On this I
was able to find a distinctly flagellated specimen suitable for
measurement by the extinction method. The flagellum could be
plainly seen with an apochromatic l/6th of 0*98 N.A. used with
a full cone and screen, and it became invisible when the N.A.
was gradually cut down to 0*42 by means of an iris diaphragm
over the top lens of the objective, thus making the diameter of
the flagellum 0*00000S91 (1/1 1 2,200th) in., or 0*226 fx.

Afterwards a balsamed-stained, flagellated specimen of the
tubercle bacillus was found. This was more difficult to see, and
the flagellum was thought to be much finer than that of the
B. termo. A 1/8 tli apochromat of 1*4 N.A. was employed to
measure this. When the N.A. was cut down to the vanishing
point and tested with the Abbe apertometer, it was found to bv
exactly 0*42, thus making the diameter of the tubercle bacillus
flagellum precisely equal to that of the B. termo. It may here
be mentioned that the existence of the tubercle bacillus flagellum,
discovered by Mr. Nelson, has been denied. It has, however,

A. A C. ELIOT MERLIN ON THE MINIMUM VISIBLE. 391

been observed by many microscopists, including myself, and has
been beautifully photographed by Mr. Nelson.*

Now the flagellum of B. termo was most carefully measured
by the late Dr. Dallinger, and his results were embodied
in a paper entitled " On the Measurement of the Diameter
of the Flagella of Bacterium termo : a Contribution to the
Question of the ' Ultimate Limit of Vision ' with our Present
Lenses." f Two hundred measurements were made by means of
a fine pencil mark made over half or two-thirds, not over the
whole, of the camera-lucida image of the flagellum. The labour
entailed may be judged from Dr. Dallinger's statement: "Now
I made fifty separate drawings and measurements with each
of the four lenses, the same conditions being observed in each
case. The results expressed in decimal fractions are as follows,
viz. :

" 1. The mean value of fifty measurements made with the
1/1 2th in. objective gives for the diameter of the flagellum
000000489208.

" 2. The mean value of fifty measurements made with the
l/16th in. objective gives 0-00000488673.

" 3. The mean value of fifty measurements made with the
l/25th in. objective gives 0-00000488024.

" 4. The mean value of fifty measurements made with the
l/35th in. objective gives 0-00000488200.

" We thus obtain a mean from the whole four sets of measure-
ments, which gives for the value of the diameter of the flagellum
of B. termo 0*00000488526, which, expressed in vulgar fractions,
is equivalent to 1 /204700th of an inch nearly; that is to say.
within a wholly inappreciable quantity."

These classical measurements of the diameter of the B. termo
flagellum are of the greatest importance, for by their means the
accuracy of the extinction method is demonstrated, which in turn
serves to confirm the exactness of the late Dr. Dallinger's results.
Assuming that a W.A. of 8 was employed, the necessary anti-
point correction by Mr. Nelson's amended table is 0*000005 13th in.,
which,addedtoDr.Dallinger'smean,makes0*00001001(l/99,900th)
in. for the true diameter of the flagellum, as against 0*00000891

* Journ. Q.M.C., Ser. 2, Vol. XI. PI. 22.
f Ibid., 1878, pp. 109-75.

392 A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE.

(1/1 12,200th) in., the diameter obtained by me from Dr. Coles's
specimen by extinction measurement. The latter method is
certainly not second to Dr. Dallinger's in exactness, whileit is
undoubtedly less laborious. Through no fault of his own, Dr.
Dallinger's uncorrected figures put the diameter of the flagellum
at half its true dimensions.

Journ. Quekett Microtcopical Club, Ser. 2, Vol. XII., No. 75, November 1014.

39:;

REMARKS ON TWO SPECIES OF AFRICAN VOLVOX.

By Charles F. Eousselet, F.R.M.S.
(Read October 21th, 1914.)

The slides of two species of African Volvox which I am
exhibiting to-night have a history of unusual interest.

It will be remembered that at the meeting of this Club on
October 25th, 1910, a paper was read by Prof. G. S. West of
Birmingham University, in which two new species of Volvox
from Africa were described.

One of these, Volvox africames, of small size and oblong in
shape, was found in a Plancton collection made in July 1907
by Mr. R. T. Leiper, of the Egyptian Government Survey, near
the northern shores of the Albert Nyanza. I received a very
small quantity of this collection for the purpose of determining
the Rotifera it contained, and found these pretty oval colonies of
Yolvox, as did also Prof. West, who had received a similar
sample, in order to name the various fresh-water algae
contained therein.

The other species is of very much larger size (as much as
l/20th inch in diam.), of spherical shape and densely crowded with
cells on its surface (estimated at 50,000 cells in one of the larger
Colonies), was found by myself on the occasion of the visit of the
British Association to South Africa in September 1905 at
Gwaai Station in Rhodesia, about half-way between Bulawayo
and the Victoria Falls of the Zambesi ; the train stopped for
half an hour at this station by the side of a shallow pool formed
by the Gwaai River, and as usual I jumped out of the train with
my collecting- net and bottle and secured a dip from the pool.
As the train went on I examined the contents of my bottle, and
besides various Rotifera I noticed some large colonies of Volvox.
The whole collection was put up in formalin, and eventually the
specimens of Volvox were handed over to Prof. West for
description, which was done in our Journal in November 1910.*

Of both these African Species of Volvox vegetative colonies
only had been found, and Prof. West expressed his regret that
the sexual colonies in various stages were not represented, so
that his description was necessarily incomplete.

This closed the first stage of the story.

In May 1912 Dr. A. W. Jakubski published in the Zoologischer
Anzeiger a paper on Rotifera collected by him in the Ussangu
Desert in German East Africa, in which several new species of
Distyla were figured and described. At that time Mr. James
Murray was writing papers on the Rotifera of Australasia and
South America and in particular was studying the family of the

* Journ. Q.M.C., Ser. 2, Vol. XL, p. 99-104.

O

94 C. F. ROUSSELET ON TWO SPECIES OF AFRICAN VOLVOX.

Cathypnidae, and we considered it very desirable to obtain,
if possible, specimens of the new species described. So after I
had ascertained that the author was working at the Zoological
Institute at Lemberg University I wrote to Dr. Jakubski
asking him to be good enough to send me a little of the material
containing the species of Rotifera. Some time in the spring of
1913 the Doctor very kindly sent a few slides and also about eigh-
teen tubes of Plancton material collected in German East Africa.
By this time Mr. James Murray had left England on his way to
the disastrous North Canadian Arctic Expedition, from which
he has not returned, and being myself much occupied with other
work, 1 delayed the examination of this material until the spring
of the present year, when I received a polite reminder from the
sender asking for the return of his tubes as soon as convenient.
This request obliged me to look over the contents of the tubes
without further delay, which was clone in May and June last.

In his paper the author states that in deserts of German
East Africa pools and ponds are rare and can only be found after
heavy rainfalls, and are then shallow and last a very few weeks
only, but often develop a considerable amount of Plancton

organisms.

In two of the tubes, amongst various Rotifera, I was surprised
and fortunate to come across numerous colonies of Vol vox
which I at once recognised as the same two species from
Africa described by Prof. West four years previously. Moreover
both species were present in various sexual stages with
androgonidia and oospores, the male and female colonies, as
well as the vegetative colonies.* The ripe star-shaped oospores
of the large Volvox Rousseleti in particular are very fine and
remarkable, and these specimens will now enable Prof. West
to describe the complete life- history of both these African species,
which appear to be widely distributed in that continent, though
not as yet known from any other part of the world.

After completing my examination of the material I returned
all the tubes to Dr. Jakubski at Lemberg in Galicia early in
July, but have not heard whether they reached him. The
tragedy of the situation is that at the end of the same month
war was declared and Lemberg (Lwow) was one of the first
towns of importance taken and occupied by the Russian army,
and it is at present impossible to ascertain what has become of
either my correspondent or his collection of specimens.

You will agree that it was a piece of extraordinary and
remarkable good luck that these collections came into my hands
and at this particular time.

* Slides were exhibited by Mr. Eousselet showing the various sexual
stages.

Joum. Quekctt Microscopical Club, Her. 2, Vol. XII. , No. 75, November 1914.

395

REPORT ON THE CONFERENCE OF DELEGATES OF
CORRESPONDING SOCIETIES (BRITISH ASSOCI-
ATION) HELD AT HAVRE, 1914, BY INVITATION OF
THE ASSOCIATION FRANCAISE POUR L'AVANCE-
MENT DES SCIENCES.

{Bead October 27th, 1914.)

To the President and Council of the Quehett Microscopical
Club, London.

As your Delegate I attended the Havre Congress of the
French Association, which began on Monday, July 27th. The
Opening Meeting was held in the Grand Theatre, where Monsieur
Armand Gautier, the President, welcomed the members and
delivered an address. On behalf of the English members
Sir William Ramsay addressed the meeting in French. In the
evening there was a reception by the Mayor and Corporation
in the Town Hall. On the Tuesday I attended a Conference
of the Delegates of Corresponding Societies in the Town Hall,
when Sir E. Brabrook read a discourse on behalf of the Chair-
man, Sir H. G. Fordham, who was absent, " On the History
of British Association Conferences of the Delegates," of which
it appears Mr. John Hopkinson was the founder. Mr. Hop-
kinson read a paper on "Local Natural History Societies and
their Publications," in which he advocates certain rules in
the publication of Transactions which would render them more
easily capable of being referred to and quoted by inquirers
or the bibliographer, and at the same time save expense in
making reprints for distribution by the authors.

Sectional Meetings took place on the Tuesday and Wednesday,
although clouds were then gathering on the political horizon, and
some presidents of Sections did not appear. On the Thursday,
July 30th, the Congress went on an excursion by train and
boat up the River Seine as far as Rouen, visiting many historical
places of interest and some famous old and ruined cathedrals
and ancient Roman settlements, such as Lillebonne, Caudebec,
Jumieges, La Bouille, on the way.

On the following day, Friday, more meetings of Sections w T ere
Journ. Q. M. C., Series II. No. 75. 28

396 REPORT ON THE CONFERENCE OF DELEGATES HELD AT HAVRE.

held, but were very poorly attended, as the political outlook was
more and more threatening and many members were called away
and left hurriedly.

On Saturday, August 1st, most presidents and secretaries of
Sections had gone and only a very few meetings took place. On
that morning at the Zoological Section I read a short paper
in French on " Pedalion or Pedalia, a Question of Nomenclature
in the Class Potifera." About midday a Government announce-
ment or " Decret " was placarded at the Town Hall and at
Post Offices ordering a general mobilisation of the French Army,,
to commence at midnight, when the Congress broke up.

I left Havre the same night by steamer for Southampton r
where I arrived on Sunday morning, about three hours late, the
boat having been held up several times in the Channel by
torpedo-boats. Thus ended a most tragic meeting of a Congress
for the Advancement of Science.

(Signed) Charles F. Pousselet.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 75, November 1914.

o\n

PEDALION OU PEDALIA; UNE QUESTION DE
NOMENCLATURE DANS LA CLASSE DES ROTIFERES.

Par Charles F. Rousselet.

[Paper read by the author as the Queliett Club'' a Delegate to the Conference
of Delegates of Corresponding Societies of the British Association held at
Havre by invitation of the Association Franqaise pour V Avancement des
Sciences. Section de Zoologic, Seance du l er A out 1914.]

Au 6 me Congres de l'Association Frangaise pour l'Avancenient
des Sciences term au Havre en 18"7 M. Jules Barrois presenta
un memoire portant le titre: "Sur 1'anatomie et le developpement
du Pedalia mira." (Seance de la Section de Zoologie du30Aoiit
1877.)

Or en 1871 le Dr. C. T. Hudson avait decouvert dans une mare
d'eau douce a Clifton pres de Bristol un Kotifere extraordinaire,
ayant six membres arthropodiques, l'un sur la face ventrale, un
second sur la dorsale, et deux de chaque cote du corps, au moyen
desquels 1'aniinal peut nager et avance dans l'eau par petits
sauts, semblables aux mouveruents des larves des crustaces
Cyclops. Hudson noinma l'animal Pedalion mirum.

En examinant ces jours le volume des Comptes rendus du
Congres de 1877 j'y trouve a la page 661 un Extrait de la com-
munication de Barrois portant le titre ci-dessus. On voit que le
nom de Pedalion a ete change en celui de Pedalia. En lisant
plus loin on y trouve les phrases suivantes :

" M. J. Barrois a ete conduit par ses etudes sur les Bryozoaires
a considerer la forme primitive de ces animaux comme comparable
a l'etat adulte des Botiferes. Pour elucider cette question
M. Barrois a entrepris au laboratoire de Wimereux l'etude de
l'embryogenie du genre Pedalion si interessant par la diversity de
ses organes appendiculaires et dont une espece est assez commune
a Wimereux. Ce Pedalion est une espece marine. II presente,
outre les deux epaulettes ciliees, six lambeaux d'epithelium
ciliaire qui forment par leur reunion une couronne presque com-
plete; les organes appendiculaires de la face orale sont au nombre
de six : quatre pointes chitineuses et deux boutons a cils raides ;
les points oculiformes sont au nombre de trois, dont deux
appartiennent a la face orale."

On voit que le nom de Pedalion est mentionne deux fois dans
cet extrait, tandis que celui de Pedalia n'y est pas nomme du
tout, ni y trouve-t-on une raison quelconque pour ce changement
de nom, qui se trouve uniquement dans le titre du memoire de
M. Barrois.

398 C. F. ROUSSELET ON PEDALION OU PEDALTA.

La question done s'impose : qui a ecrit ce titre ? est-ce
M. Barrois, ou le redacteur des Comptes rendus du Congres ?
J'ignore si le memoire de Barrois a ete publie en entier quelque
part, et je serai bien content d'en etre informe. La Revue
Scientifique du temps (No. 13, du 29. Sept. 1877) a publie le
merne extrait, sans le titre cepenclant, et par consequent le mot
Pedalia n'y est pas mentionne, mais seulement celui de Pedalion
a deux fois.

II y a autre chose encore : par la description que donne Barrois
il ressort bien clairement que son Botifere n'etait pas Pedalion,
qui ne vit pas dans la mer, n'a que deux yeux, n'a pas d'epaulettes
ciliees, ni de couronne ciliee en six lambeaux, ni six organes
append icul aires sur la face orale. Toute cette description
s'applique parfaitement a tine espece marine du genre Syncbaeta
(probablement S. triophthalma Lauterborn, qui porte ses ceufs
suspendus a la pointe de son pied en nageant), mais pas du tout
au Pedalion mirum de Hudson, qu'on rencontre un peu partout
en ete dans des mares d'eau douce.

II existe deux autres especes de Pedalion (P. fennicum Levander
et 7-*. oxyure Sernow) qui se trouvent tous deux dans les eaux
saum aires en Asie, en Egypte, en Amerique et en Australie,
mais aucune espece n'a encore ete decouverte en mer.

Par suite de 1'application des regies internationales de nomen-
clature le nom du genre Pedalion doit tomber, ce nom ayant ete
applique precedemment a un poisson (Swainson 1832), et a un
mollusque (Solier 1847).

II est done utile et necessaire de rechercher qui a le premier
employe le nom de Pedalia, et j'invite les membres de la Section
de Zoologie de bien vouloir me communiquer le memoire complet
de M. Jules Barrois s'il existe, ou toute autre information qui
pourrait elucider cette question.

Je ne parle pas de l'Hexarthra de Schmarda, qui pourrait
tres bien etre une espece encore plus ancienne de Pedalion ; e'est
une autre question que j'espere pouvoir resoudre sous peu, apres
m'avoir procure des peches dans le meme marais d'eau saumatre
a El Kab en Egypte oil Schmarda a decouvert son Hexarthra en
Mars 1853.

II resulte de cet expose que M. Jules Barrois (ou peut-etre
quelqu'autre personne) a non seulement change le nom de
Pedalion en celui de Pedalia, mais encore l'a applique a un
Svnchaeta.

Joarn. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 75, Koccmbc,- 1914.

399

THE LIBRARY.

BOOKS PURCHASED SINCE JANUARY 1914.

Optical Convention. Vol. II. 1912.

Sylloge Algarum Omnium. Vol. II. Sect. II. J. Bapt.

De Toni, 1892.
Bacteriological Examination of Food and Water. Wm.

G. Savage, B.Sc, M.D., D.P.H., 1911

BOOKS AND PHOTOGRAPHS PRESENTED SINCE

JANUARY 1914.

Revue Suisse de Zoologie a propos de Rotiferes. Vol. XXII.
No. 1. January 1914. E. Penard.

Presented by the Author.

Sylloge Algarum Omnium. Vol. II. Sect. I. Raphideae.
J. Bapt. De Toni.
Presented by the Author.

My Sayings and Doings. Rev. Win. Quekett.
Presented by G. W. Watt.

Cothurindes Muscicoles. E. Penard.
Presented by the Author.

Sur quelques Teulaculiferes Muscicoles. E. Penard.
Un curieux Infusoire, Lbgendrea bellerophon. E. Penard.

Presented by the A uthor.

Eighty Photographs of Drawings of Rotifera. By F. R.
Dixon -Nuttall.
Presented by F. R. Dixon-Nuttall.

Eighty Photographs of Rotifera.
Presented by J. B. Groom.

Royal Society of Victoria : Further Notes on Australian
Hydroids. Part II. W. M. Bale, F.R.M.S.

Presented by the Author.

400 THE LIBRARY.

< )donaten-Studien. C. Weseriberg-Lund.
Presented by the Author.

WOHNUNGEN UND GEHAUSEBAU DER StJSSWASSERINSEKTEN. C.

Wesenberg- Lund.
Presented by the Author.

FoRTPFLANZUNGSVERHALTNISSE PAARUNG UND ElABLAGE DER

Susswasserinsekten. C. Wesenberg-Lund.
Presented by the Author.

Commonwealth of Australia, Department of Trade and
Customs : Fisheries. Biological Results of Fishing Ex-
periments carried on by T.I.S. Endeavour. 1909-14.

Report on the Hydroida Collected in the Great Australian
Bight and other Localities. W. M. Bale, F.R.M.S.

Presented by the Author.

The Journal of Micrology. Parts I. -IV.
Presented by H. Edwards.

For Sale 50 copies reprints of Paper " Lagenae of the
South- West Pacific Ocean," by Henry Sidebottom. Two Parts.
Price 2s. Gd. Application should be made to the Librarian.

401

THE CLUB CABINET.

The following Slides have been added to the Cabinet since
October 1912 :

Protozoa.

Presented by G. T. Harris.
K.A. 106. Actinosphaerium Eichomi (binary fission).

Infusoria.

Presented by J. C. Kaufmann.
K.A. 102. Euglena sp.

Presented by J. Burton.
107. Euglena viridis.

Presented by G. T. Harris.

103. Ephelota sp. (stained to show nucleus).

104. Ephelota sp.

105. Noctiluca miliar is.

Hydrozoa.
Presented by G. T. Harris.

(s = stained.)

M.A. 4:. Aglaophenia pluma, s.

50. Aglaophenia pluma (gonophores).

51. Bougainvillia, muscus.
14. Cah/cella syringa.

23. C ampamdaria Jlexuosa, s.

52 . C ampamdaria flexuosa.

53. C ampamdaria neglecta.

54. Clara carnea.

402 TJ1E CLUB CABINET.

M.A. 55. Clava carnea, s.

56. Clava midticornis, s.

57. Clava squamata, s
17. Clytia Johnstoni, s.

58. Clytia Johnstoni.

91. Clytia Johnstoni (medusa).
19. Cordylophora lacustris, s.

59. Cordylophora lacustris (with compound bud), s.
8. Coryne pus ilia, s.

60. Coryne vaginata (gonophores), s.

61. Coryne vaginata [with epiphytal Licmophora /label -

lata).

62. Coryne vaginata, s.

63. Eudendrium insigne,

64. Eudendrium insigne [with Ephelota : Infusorian).

65. Gonothyrea Loveni.

66. Halecium Bcanii.

67. Hydra fusca.

68. Hydra viridis (ovary and testes), s.

69. Hydra vulgaris, s.

92. Lizzia Blondini (medusa).

93. Lucernaria fascicularis (medusa).

70. Obelia dichotoma, s.

71. Obelia dichotoma.

72. Obelia geniculata, s.

73. Obelia geniculata.

74. Perigonimus sessilis.

75. Plumularia echinulata.

76. Plumularia echinulata.

77. Plumularia echinulata, s.

78. Plumularia echinulata, s.

79. Plumularia halecoides, s.

80. Plamidaria halecoides.

81. Plumidaria pinnata.

82. Plumularia setacea.

83. Plumidaria setacea.

84. Plumularia setacea (metatophores).

85. Plumularia siinilis, s.

86. Plumularia similis.

87. Podocoryne areolata, s.

THE CLUB CABINET. 403

M.A. 28. Sertularia frfiada.

88. Sertularia pumila, s.

89. Sertularia pumila.

90. Serti'liiri'i pwmila.

Echinodermata.
Presented by J. Burton.
N. 19. Plates of Taeniogyrus A llani.

Rotifera.
Presented by J. C. Kaufmann.

Rot. 246. Lacinularia elliptica.

Turbellaria.

Presented by H. Whitehead.

Series 20 : v:ith descriptive notes and diagrams.

Jficrostomum lineare.

Phaenocora (Derostomum) punctatum.

Daly el Ha viridis.

Daly ell ia diadema.

Gyratrix herm aphrodit us.

Dendrocoelum lacteum.

Planaria alpina.

Planar ia alpina : tr. and long. sees.

Planaria gonocephala.

Polyeelis nigra.

Poly celis nigra : tr. sec.

Polyeelis cornuta.

V B. 35. Tr. sec. (serial) of a Planarian.

Insecta.

Presented by T. A. O'Doxohoe.

R. 402. Scales of Templetonia crystallina.
403. Scales of Seira Buskii.

Presented by F. H. jST. C. Kemp.
399. Xaucoris cimicoides (adult).

404 THE CLUB CABINET.

Polyzoa.

Presented by G. T. Harris.

M.B. 33. Aetea anguina.

84. Bowerbankia imbricata.

85. Pedicellina cernaa.

80. Pedicellina cemua, var. gracilis.

Physiological Histology.

Purchased. (With descriptive, illustrated text.)

Series 10. The Shin.

Human scalp, with hair : long, and tr. sees.

Human scalp, with hair : long, sec, injected.

Human skin, with perspiration glands : long. sec.

Human skin, stages of development of perspiration glands : long.

sec.
Human skin, with blood vessels injected : long. sec.
Skin of Dog, with elastic fibres : long. sec.
Tactile hairs of Ox, with blood sinus : tr. sec.
Human hair, stages of development : long. sec.
Human nail : lon^. sec.

*&

Series 11. Muscle, bone, etc.

Human embryo, finger and arm : long. sees.

Muscle of Ring Snake, with motor nerve plates.

Muscle of Dog : tr. sec. and long, sec, injected.

Tendon of Ox : tr. sec.

Cervical ligament of Ox : sec.

Bone of Ox : long, sec

Cranial bone of Dog : sec.

Joint of Rabbit : median sec. ,

Series 12. Central nervous system.

Spinal cord and ganglion of Cat : tr. sec.

Spinal cord of Cat (Golgi preparation : cell impregnation).

Spinal cord of Dog : tr. sec.

Cerebral cortex of Cat (Golgi preparation : cell impregnation).

THE CLUB CABINET. 405

Cerebellum of Cat (fibre impregnation).
Cerebrum of Man (fibre impregnation).
Pineal gland of Ox : tr. sec.
Pituitary gland of Ox : tr. sec.
Embryonic spinal cord of Fowl.
Embryo of Rabbit : tr. sec.

Series 13. Reproductive organs.

Penis of Bull : tr. sec.
Glandula vesicularis of Bull : sec.
Spermatozoa of Bull.
Testis of Mouse : tr. sec.
Umbilical cord of Child : tr. sec.
Gravid uterus of Pig : tr. sec.
Oviduct and ovary of Dog : tr. sees.
Ovary of new-born Kitten : tr. sec.
Mammary gland of Cow : tr. sec.

Series 14. Respiratory and urinary organs.

Lung of Cat : injected.

Lung of Cat (elastic fibres).

Lung of Dog (cell pigmentation).

Trachea of Cat : tr. sec.

Kidney of Rabbit : injected.

Kidney of Mouse : tr. sec.

Bladder of Ox : tr. sec.

Supra-renal capsule of Ox : tr. sec.

Embryonic okenian body of Pig : tr. sec.

Thyroid gland of Man.

Series 15. Tic Eye.

Cornea of Ox (gold impregnation).

Choroid of Ox, showing pigment cells.

Retina of Ox.

Optic nerve of Ox : med. sec.

Eyelid of Calf : med. sec.

Lachrymal gland of Ox.

Glands of nictitating membrane of Rabbit.

406 THE CLUB CABINET.

Anterior half eye of Ox, without lens : hor. sec.
Eye of embryo Chick : med. sec.
Eye of embryo Pig : med. sec.

Series 16. Organs of hearing, smell and touch.

Auditory organ of Cat (sensory hairs of ampullae).

Auditory organ of Cat, membrana tympani : tr. sec.

Auditory vesicle of embryo Rabbit : long. sec.

Cochlea of Guinea Pig : med. sec.

Nasal mucous membrane of Cat : tr. sec.

Nasal mucous membrane of Rabbit, respiratory portion.

Olfactory mucous membrane of Rabbit : tr. sec.

Circum vallate papillae of Ox : mecl. sec.

Papilla f oliata of Rabbit : tr. sec.

Pacinian corpuscles in human skin.

Series 17. Circulatory and blood-forming organs.

Renal artery and vein of Pig : tr. sec. (fibres stained).

Renal artery and vein of Pig : tr. sec. (cells stained).

Human muscle of heart : tr. sec.

Embryo of Rabbit : tr. sec. in region of heart.

Human blood : film preparation.

Human blood : haemin crystals.

Red bone marrow of Pig.

Human spleen : sec.

Human thymus gland (child) : sec.

Lymphatic gland of Pig : sec.

Presented by C. L. Curties.

(Slides remounted by the late Sir Benjamin Ward Richardson

over 50 years ago.)

X. 428. Medulla of Cat : tr. sec, injected.

429. Tongue of Rat : tr. sec, injected.

430. Duodenum of Turtle : tr. sec.

431. Intestine of Guinea Pig : vert, sec, injected.

432. Jejunum of Cat : vert, sec, injected.

433. Large intestine of Pig : tr. sec, injected.

434. Retina of Rat : injected.

435. Toe of Mouse : long, sec, injected.

THE CLUB CABINET. 407

X. 436. Human tooth : tr. sec.

437. Human large intestine : vert, sec, injected.

438. Human jejunum : vert, sec, injected.
440. Human sole of foot : vert. sec.

Freshwater Algae.
Presented by J. Burton.

B. 112. Anabaena circinalis.

122. Apiocystis Brauniana.

119. Batrachospermum moniliforme.

114. Bulbochaete sp.

117. Chaetophora incrassata.
116. Choaspis stictica.

(Chrobcoccics turgid us.
' {0 oelosphaerium Kuetzingianum.

115. Cladophora flavescens.

127. Cladophora sp. (Lake Zurich).
B. 121. Clathrocystis aeruginosa.

123. Coleochaete scutata.
125. Cosmarium nitidulum.

( Cylindrospermum stagnate.
' {Lyngbya sp.
125. Jlerismopedia sp.
41. Micrasterias rotata.

128. Oscillator ia princeps.
113. Pandorina morum.

129. Sphaeroplea annulina.

118. Spirogyra sp.

120. Tolypothrix la/iata.

130. Trichodesmium Ehrenbergi (Atlantic Ocean).
53. Zygnema sp.

Presented by Exor. of J. M. Allen.
B. 111. Ballia pulchrinum.

Diatomaceae.

Presented by S. E. Akehurst.
A. 690. Amphipleura pellucida (realgar).

408 THE CLUB CABINET.

Presented by J. Burton.

A. 688. Rhipodophora meneghiniana, on Ectocarpus.
689. Achnanthes sp., conjugating on Marine Algae.

Purchased : mounted in styrax.

A . 691. A ctin ocyclus pruinosus.

692. Actinoptychus Bismarckii.

693. Actinoptychus Grunowii.

694. Actinoptychus hexagonus.

695. Actinoptychus maculatus.

696. Amphora Grevillei.

697. Asterolampra aemulans.

698. Auliscus mirabilis.

699. A uliscus permagna.

701. Biddulphia Roperiana (showing mode of growth).

702. Biddulphia Tuomeyi.

700. Brebissonia Weissjlogii.

703. Campylodiscus stellatus.

704. Clyphodesmis Challenger ensis.

705. Cocconeis extravagans.

706. Diploneis exemeta.

707. Kntogonia Daveyani.

708. Gymatopleura solea.

709. Hantzschia marina.

710. Mastogloia cruciata.

712. Navicula carinifera.

711. Navicula follis.

713. Navicula gemmulatula.

714. Navicula irrorata.

715. Navicula luxuriosa.

716. Navicida notabilis.

717. Nitzschia scalaris.

718. Omphalopsis australis.

719. Opephora Schivartzii.

720. Pinnularia dactylis.

721. Plagiogramma validum.
252. Pleurosigma balticum.

722. Podocyrtis adriaticus.

723. Raphoneis (uujjhi.ceros.

THE CLUB CABINET. 40!)

A. 724. Stephanopyxis Campeachiana.
725. Stictodiscus Nova- Zealand ic us.
72G. Stictodiscus par ellel us, var. gibbosa.

727. Surirella lata, var. robusta.

728. Surirella Macraeana.

729. Terpsinoe americana.

730. Triceratum dejinitum.

731. Triceratum favus, var. quadrata.

732. Triceratum favus, var. maxima.

733. Triceratum fractum.

734. Triceratum grande.

735. Triceratum Nova-Zealandicus.

736. Triceratum Robertsianum.

Fungi.

Presented by J. Burton.

C. 190. Sphoeria herbarum.
191. Sphoerella rusci.

Bacteria.
Presented by J. Burton.
0. 140. Cohnia roseo-persiciaa.

Plant Structure.
Presented by C. J. H. Sidwell.

E. 38. Leaf of Hydrocharis morsus-ranae\ ri tl n

q~t * * j ,- -Cellular structure,

of. Leai oi lradescantia virginica J

E.A. 55. Leaf of Croton zambesicus

58. Leaf of Cynoglossum micranthum

52. Leaf of Onosma alboroseum
57. Leaf of Onosma stellulatum

53. Leaf of Onosmodium carolinianum
24. Leaf of Rhododendron Dalhousia
56. Leaf of Rhododendron Maddeni
51. leaf of Trirhodpsma indicum

54. Leaf of Trichodesma khasiana

Hairs and
glands.

410 THE CLUB CABINET.

Seeds.

Presented by C. J. H. Sidwell,

G. 43. Anagallis arvensis.

41. Castilleja sp.

46. Castilleja Cidbertsoni.

43. Cerastium glomeratum.

39. Delphinium niacrocentron.

47. Linaria vulgaris.

42. Mohavea viscida.

45. Pedicular is Frederica-Augusti.

44. Picrorhiza Kurrooa.

40. Tricholoena rosea.

ill

PROCEEDINGS

OP THE

QUEKETT MICROSCOPICAL CLUB.

At the 497th ordinary meeting of the Club, held on March 24th,
1914, the President, Prof. A. Dendy, D.Sc, F.R.S., in the chair,
the minutes of the meeting held on February 24th were read and
confirmed.

Messrs. C. W. Engelhardt, Harry Albert St. George, E.
Hermann Anthes, Felix R. W. Brand, Victor M. E. Koch,
Francis W. Lloyd, Leonard R. Gingell and His Excellency
Nicholas Yermoloff, K.C.Y.O., were balloted for and duly elected
members of the Club.

*

The list of donations to the Club was read, and the thanks of
the members voted to the donors.

The President said : " My attention has been called to the
fact that Mr. Powell, one of our oldest and best-known members,
is present this evening. I am also informed that Mr. Powell
celebrated his eightieth birthday on Saturday last. May I be
allowed, on behalf of the Club, to offer him our sincere con-
gratulations on this occasion, and to express our satisfaction that
he is still able to be present at our meetings ? "

Mr. J. W. Ogilvy (Messrs. Leitz) exhibited an illuminator for
opaque objects which consists of a bull's-eye and a stage-condenser
fitted to a bar which is carried on a stand having universal
movements. Being in one piece, time is saved in setting up the
apparatus.

Mr. N. E. Brown, A.L.S., read " Some Notes on the Structure
of Diatoms."

An animated discussion followed the paper, in which the
President and Messrs. O'Donohoe and Ainslie took part, and to
which Mr. Brown replied.

A hearty vote of thanks was given to Mr. Brown for his
interesting paper.

The Hon. Sec. read a paper, communicated by Mr. E. M.
Nelson, F.R.M.S., on " A New Object-glass by Zeiss, and a New
Method of Illumination."

Journ Q. M. C, Series II. No. 75. 29

412 PROCEEDINGS OF THE

Messrs. Zeiss exhibited the new oil-immersion l/7th on four
microscopes, and the thanks of the meeting were accorded to
Messrs. Zeiss and to M. Koch, who represented the firm.

At the 498th ordinary meeting of the Club, held on April 28th,
1914, the Vice-President, Mr. D. J. Scourfield, F.Z.S.,F.R.M.S.,
in the chair, the minutes of the meeting held on March 24th
were read and confirmed.

Messrs. Edward Carlile, Francis Cooley-Martin, Gerald Burton
Burton-Brown, M.D., Francis Edward Robotham and Daniel
Arthur Davies, jun., were balloted for and duly elected members
of the Club.

The list of donations to the Club was read and the thanks of
the members voted to the donors.

The Hon. Sec. read a note on " A New Low-power Con-
denser," communicated by Mr. E. M. Nelson, F.B..M.S.

Mr. C. Lees Curties (Messrs. C. Baker) exhibited both the
low -power condenser designed by Mr. Nelson and also a simple
centring-stop holder which he had suggested.

Replying to a question, Mr. C. Lees Curties said that the
aperture of the condenser was 0*55. On account of its long
working distance, the condenser would be particularly useful for
dark-ground illumination when examining pond-life in a
trough.

Mr. M. A. Ainslie said that the Leitz achromatic condenser
with the top off had an aperture of 0'6, and a working distance of
one-third of an inch. He would suggest that, when necessary,
the condenser should be decentred, in order to centre the stop.
He frequently did this with low powers, when necessary.

Votes of thanks to Mr. Nelson and to Mr. Curties were pro-
posed and carried unanimously.

Mr. N. E. Brown, A.L.S., gave an account illustrated with
fresh specimens of the flower and a coloured drawing of a longi-
tudinal section of " The Fertilisation of Vinca minor" He
said that a very interesting microscopic object was concealed in
this flower. As regards its fertilisation, a special interest was
connected with the flower of the periwinkle. The fruit of this
plant is extremely rare, not only in this country, but also on the
Continent. The flower has a. very remarkable structure, and a

QUEKETT MICROSCOPICAL CLUB. 413

section exhibiting the stigma has several points of interest. At
the bottom of the tube are two large glands which secrete honey,
one on each side of the ovary. The ovary has two carpels, which
are separate, but are united at the top into a single style. This
goes up, and at the top expands into a wing-like disc, and termi-
nates with a crown of hairs like a sweep's brush. Some of these
hairs turn down into five little tufts, forming little alcoves, which
play very important functions. From the corolla arise five
stamens. The anthers are raised above, and are so curved over as
to enclose the whole and prevent ingress except between each pair
of stamens. The anthers open while in the bud, and then shed
their pollen, which, when the flower opens, is seen to be deposited
in five little heaps. Underneath the wheel-like formation, often
spoken of as a stigma, we find a frill-like, orange-coloured body,
which is not of the same depth all round, but opposite the little
alcoves already referred to deepens slightly. The true stigma is
formed by this curtain, or frill, and there we find the true stig-
matic tissue. Now as regards fertilisation. Insects (bees) come
for the nectar situated at the base. Grooves guide the tongue
between two anthers and past the upper ledge of the shelf, or
frill. Here it passes the little masses of pollen, which are slightly
glutinous, and, before reaching the honey-glands, comes in contact
with a wet, viscid fluid. ^Yhell the tongue is withdrawn, the
smeared surface comes in contact with the mass of pollen, which
adheres to it. But the plant does not want to part with all its
masses of pollen, and so some is scraped off the proboscis by the
projecting hairs, and remains until the visit of another bee,
which, perhaps, has already visited a periwinkle flower. The
tongue passes down past the stigmatic frill ; but in coming back
scrapes the pollen off on the under side, no trace of pollen
remaining on the part of the tongue previously smeared with
the viscid matter. This is the manner in which the plant is
fertilised. Last year the speaker had examined many plants in
order to see if they had been fertilised. It is commonly stated
that V. minor is infertile to its own pollen, and so seeds are rare.
Nearly all plants in one locality are probably products of one
plant, and have not come from seed. Of the plants examined,
70 per cent, had been fertilised by insects ; but no fruit of any
kind developed on the clump under observation. Mr. Brown this
year had fertilised one hundred flowers ; but it is yet too early to

414 PROCEEDINGS OF THE

be able to report any results. This year was noticeable for a
great dearth of pollen, all the anthers being more or less barren.
He awaited with interest the result of his artificial pollination.

The Chairman said that at first thought it might possibly be a
case of over -elaboration.

Mr. R. Paulson asked if Mr. Brown had cut sections to see if
any of the pollen grains had thrown out tubes. He preferred to
distinguish between the terms " pollination " and " fertilisation."
As is well known, there are some plants in the British flora
where pollination does take place, but which are infertile. As
an instance he would mention the lesser celandine Ranunculus
fizaria. Had Mr. Brown ever seen any seeds of this plant 1 It
might be imagined that its seeds would be very numerous ; but
this is not the case. It does seem that in many plants we have
instances of over-elaboration. He would instance orchids and
violets and especially with regard to violets. Violets produce
abundant seed, not by the attractive flowers, but by little green
flowers which are usually missed by the ordinary observer.
These little green flowers never open and the anthers shed their
pollen directly on to the stigmas.

Mr. 0. E. Heath asked whether the pollen of Vinca minor had
been seen to form tubes.

The Hon. Secretary suggested that the pollen might be tested
practically, under the microscope, in a weak solution of sugar-
and-water. If the grains did put out tubes, he thought it would
prove the possibility of fertilisation.

Mr. Brown, replying, said that even if the pollen grains pro-
duced tubes in a sugar-and-water solution, it would be no
guarantee that they would also do so in the flower. He intended,
however, to examine the pollen and also to cut sections.
Regarding the celandine, in the South of England it seeds quite
freely. It is possibly a question of temperature. Not all violas
have cleistogamous flowers ; some usually produce seed from the
ordinary open flowers.

The Hon. Secretary (Mr. James Burton) read a note on "An
Abnormal Form of Arachnoidiscas ornatus." He wished to draw
attention to the plate of Arachnoidiscus, by Beck, in Carpenter's
The Microscope and its Revelations, a copy of which was on the
table. The drawing represented the diatoms entire and still
attached to the seaweed on which they occurred. It showed their

QUEKETT MICROSCOPICAL CLUB. 415

living form. That which we are accustomed to find on mounted
slides is only a part of the organism. He was exhibiting, under a
microscope, a slide given him by Mr. Williams, of Folkestone,
which displayed very beautifully the box-like form of this diatom.
It consists of a top and a bottom circular plate, known as valves,
to each of which is attached a ring, called by some authors the
girdle ; that of the top or lid, as it might be called fitting
outside that of the lower, or box -like, part. The whole closely
resembles an ordinary circular " chip ' ! specimen-box. On the
slide exhibited, examples of an abnormal form occur, in which
the bottom of the box has the "girdle" greatly elongated, the
"lid" still remaining shallow, as in a normal form. This struc-
ture gives the diatom, when viewed sideways, the appearance of a
cylinder, instead of that of a disc with but slight depth, and when
observed under a binocular with dark-ground illumination the
difference is very striking. The girdle is marked by circles of
lines running round, as though it were composed of superimposed
rings. On the rings are small projections or points. The
frustules are empty, and there is no appearance of the com-
mencement of dividing-walls inside, which might have indicated
that the unusual form was owing to the beginning of the process
of subdivision. In a normal form the depth was 30 /x ; in a case
where subdivision was far advanced the depth was 54 /x. In an
abnormal specimen the depth was 96 /x; another was 105 /x. The
diameter in all the forms measured is fairly constant, varying
from 105 /x to 114 /x. The abnormal form is only known to occur
in one collection of material from Mauritius, and in that the
percentage is very small. No explanation or suggested cause of
the unusual form was forthcoming.

Mr. Burton was complimented on the opportunity of bringing
this interesting slide under the notice of members.

Several members had interesting exhibits under microscopes,
Mr. G. K. Dunstall showing Flosadaria cyclops, which is worthy
of being recorded.

At the 499th ordinary meeting of the Club, held on May 26th,
1914, the President, Prof. A. Dendy, D.Sc, F.R.S., in the chair,
the minutes of the meeting held on April 28th were read and
confirmed.

Messrs. Henry Turing Peter, Sydney G. Bills and .Robert

416 PROCEEDINGS OF THE

William Buttemer were balloted for and duly elected members of
the Club.

The list of donations to the Club was read and the thanks of
the members voted to the donors.

Mr. W. R. Traviss exhibited a number of specimens of insects
in amber.

Mr. A. E. Hilton read " Some Notes on the Cultivation of
Plasmodia of Badhamia utricularis" He said that a free-
flowing mass of naked and almost undifferentiated protoplasm,
such as we have in a plasmodium of B. utricularis, suggests
opportunities for biological experiments with unusual promise of
success.

The chief purpose of this paper, Mr. Hilton said, was to place
on record the results of experiments made during the last few
months, which suggest a method of continuous cultivation of
plasmodia of B. utricularis at once simple and practicable.

The President said they were very much obliged to Mr. Hilton
for his very interesting and practical paper, which he should find
of great value to himself, as he had hitherto had great difficulty
in feeding this organism. He hoped the methods described would
come into general use for laboratory work, where the plasmodium
was very useful as an illustration. He should like to ask
Mr. Hilton if he had tried how long he could keep the plas-
modium in a dry state on the blotting-paper. Mr. J. J. Lister
at Cambridge used to feed it on fungus, but this was sometimes
difficult to get. He hoped that many members of the Club would
experiment in the manner suggested.

Replying to several questions, Mr. Hilton said the dried
sclerotium is capable of reviving after at least three years; but
it must be kept dry, and never allowed to become damp. After
so long a period, it might take four or five days to recover. He
could not say if it were possible to cultivate the plasmodium form
from sporangia. A difference in colour has been noticed in
specimens cultivated on plain bread compared with specimens
fed on the special mixture. The former are a lighter yellow
than the latter ; but various shades of yellow are present even in
one plasmodium. He had found a constant temperature of about
50 F. the best.

A very hearty vote of thanks was accorded to Mr. Hilton for
his paper.

QUEKETT MICROSCOPICAL CLUB. 417

The Hon. Secretary read a paper on " Binocular Microscopes,"
communicated by Mr. E. M. Nelson, F.R.M.S. In recent years
several binoculars have been introduced, none of which, however,
can be called new. The first, the Greenough, by Zeiss (Journal
R.M.S., 1897, pp. 599, 600), was a twin microscope a form of
binocular invented by Pere Cherubin d'Orleans nearly three
hundred years ago. The second by F. E. Ives, in 1902 {Journal
R.M.S., 1903, p. 85) is very similar to one designed by Wenham
in 1866 as a counterblast to Powell's high-power binocular, in
which the whole beam is sent into each eye. The third, a modifi-
cation of the second, by Leitz {Journal R.M.S., 1914, p. 5), and
the fourth, by Beck, which is very similar to that of Ives.

Mr. Nelson concluded his paper by some remarks on the
position of the two new binoculars. From what has been said,
it will be seen that they are a class by themselves. It would be
quite inaccurate to entertain the idea that these instruments are
a new kind of stereoscopic binocular constructed to enter into
competition with, and finally to supersede, existing binoculars of
the Wenham and Stephenson type, for they only possess the first
attribute stereoscopism in a limited manner. Their use is
confined to the employment of full Ramsden discs in each eye
that is, for work with non-stereoscopic images. When prolonged
work is undertaken with one of the new binoculars, great relief
and comfort to the eyes will be secured.

Messrs. Beck, represented by Mr. C. Beck and Mr. Creese,
exhibited two of their new model high-power binoculars, one
giving an excellent image of Pleurosigma angulation with a 1/1 2th
oil-immersion, and on the other stand a lower power exhibited to
perfection, first, stereoscopic, and, second, pseudo-stereoscopic
vision obtained by altering the tube-length. Mr. Creese also
exhibited a Wenham binocular with a l/6th objective, giving a
perfectly evenly illuminated field at 300 diameters of a section of
the eye of the drone-fly.

Messrs. Leitz's London representative, Mr. J. W. Ogilvy,
showed seven stands of their new model, with powers ranging
from 1/1 2th oil-immersion apochromat and 1,500 diameters to
1 in. and x 35. Two Leitz-Greenough models with low powers
were also exhibited. The preparations shown included Amphi-
pleura pellucida, Poclura scale, rock sections, and histological
preparations.

418 PROCEEDINGS OF THE

Mr. Nelson also sent for exhibition a photograph of a new
slide, designed by Mr. G. Nelson, for the portable Greenough, to
hold three pairs of objectives. It allows the powers to be changed
by moving the slide forward, and, in brief, is for the Greenough
what a rotating nosepiece is for an ordinary microscope.

At the 500th ordinary meeting of the Club, held on June 23rd,
1914, the Vice-President, Mr. E. J. Spitta, L.R.C.P., M.R.C.S.,
in the chair, the minutes of the meeting held on May 26th were
read and confirmed.

Messrs. Geoffrey Norman, Charles James Reeves King, William
Henry Scott, Charles Worthington Hawksley, Martin Herbert
Oldershaw and Edmund John Weston were balloted for and duly
elected members of the Club.

The list of donations to the Club was read and the thanks of
the members voted to the donors.

Mr. Watson Baker, jun., read a short paper describing a
series of sections of fossils from the Coal Measures. Many of
these were not only rare, but were almost unique in the beautiful
manner in which they showed the various structures, both of
plants and animals. They were exhibited under a number of
microscopes, lent and arranged for the occasion by Messrs.
Watson & Son. There were on view, also, whole specimens
still attached to the rock in which they were found. Mr. Watson
Baker said the specimens had been sent to him by a well-known
authority on palaeo-botany, and as many of them were of unusual
merit, he thought the Club would like to see them. He then
gave an interesting description in some detail : a condensed account
is as follows : No. 1. A specimen of the lower jaw of Elonicthys,
with teeth in situ. No. 2. Flank scales from the same. Elonic-
thys is a genus of fishes having a bony armour or a skeleton.
Devonian and Carboniferous, they existed in large numbers and
great variety, some attaining a great size. No. 3. A specimen of
the Caeleanthidae (hollow-spined fishes), which range from the
Upper Devonian to the Chalk. Specimens of these in situ were
on the table. Nos. 4 and 5 were sections of teeth of species of
shark, Diplodus equilateralis and D. gibbosus ; also an uncut
example of one of the teeth. Nos. 6 and 7. Sections of coal from
Mossfield Colliery, Longton, showing various vegetable tissues.

QUEKETT MICROSCOPICAL CLUB. 419

Microspores and Megaspores reproductive organs resembling
those of modern Lycopods were clearly evident. No. 8. Plant
remains of a similar character. No. 9. A number of Fern
sporangia, showing the annulus, etc., embedded in a matrix of
fragmentary plant remains. No. 10. A section showing the
seeds of Cordaites : a genus of fossil-plants allied to some of the
recent Gymnosperms.

The chairman remarked on the very beautiful series of micro-
scopical slides, and on the hand specimens on the table, and pro-
posed a vote of thanks to Mr. Watson Baker, which was responded
to heartily.

The Hon. Secretary read a letter from Dr. M. C. Cooke, and
extracts from others received from Alphaeus Smith, Albert D.
Michael and G. 0. Karrop, who were unable to be present, con-
gratulating the Club on its continued prosperity, and wishing
it all success in the future. These were received with much
appreciation by the meeting.

The chairman then gave a short resume of the history of the
Club. He said that though named in honour of the celebrated
Dr. Quekett, it was not founded by him, originating four or five
years after his death. It was considered by a Mr. Gibson that
an association of amateur microscopists was desirable, and he put
an announcement into Hardwicke's Science Gossip to that effect.
The idea at first seemed to be to combine music and microscopy
at the evening meetings. The suggestion was rapidly and
enthusiastically taken up, and in July 1865 the Club was
definitelv started. Soon the meetings came to be held at
University College ; but it is curious to note that some of the
preliminary ones were held in Hanover Square, so that, again
occupying rooms in Hanover Square, the Club has returned to
its old locality. Among the very earliest members Mr. Lewis's
name appears. He was elected in April 1866 forty-eight years
ago, and has held the position of honorary reporter from the
very early years of the Club. He has attended 485 out of
the 500 ordinary meetings almost certainly a record and
several of the omissions occurred only this last winter, owing
to illness and advancing years. Another very old member is
Mr. Alphaeus Smith, who held the post of hon. librarian
for forty years, and is still a member, though not on the active
list. Dr. M. C. Cooke, Mr. J. Terry, Mr. T. H. Powell, and

420 PROCEEDINGS OF THE

Mr. Millett all joined in 1865, and are still members. Dr.
Spitta referred to the work of Dr. Karop and Mr. Earland,
both of whom had been hon. secretaries in former years, and to
whom the Club was greatly indebted for its success. Lantern
photographs of Dr. Quekett and of pages of the old attendance-
books, showing names of original members, and various scenes
connected with the Club's life, were thrown on the screen.
Dr. Spitta wound up his interesting and delightfully humorous
discourse by recounting a supposed reverie (in verse) in which he
saw most of the present officers and prominent members coming
into a meeting, and detailed with delicate skill and good nature
their hobbies and characteristics. He then called upon some of
the older membersof whom a satisfactory number had been
able to attend to say a few words.

Mr. Lewis made a little speech, in which he disclaimed the
title of "veteran," as he said Mr. Powell was before him, and he
spoke of Mr. A. Smith, who joined just after him. He was able
in some respects to supplement the chairman's remarks of what
took place at the earliest meetings, and said in conclusion that
" though my recent illness has shaken my health, and I shall
have to give up many things, the last I shall give up will be the
Quekett Microscopical Club, from which I have derived much
information, and have made many old and valued friends, and no
one connected with the Club has its interests more at heart than
myself." His remarks were received with enthusiasm by the
members, who showed their appreciation by prolonged cheers.

Mr. T. H. Powell (forty-nine years a member) wound up what he
said by remarking that he always enjoyed himself at the pleasant
meetings of the Quekett. Mr. F. Enock addressed the meeting
appropriately, and was followed by Mr. Earland, who made an
interesting and humorous speech on some of his experiences as
secretary. He, like others, referred to Mr. Lewis, and rejoiced
to see him still at the seat at the reporter's table he had occupied
so long. Again the audience showed their appreciation by cheers.
Mr. Hilton followed. He pointed out that till quite recent
years, during the long career of the Club, there had been only
two librarians, owing to Mr. Smith's long tenure of the office.
He also remarked on the large attendance at the meetings now,
saying that they could not realise what it was to have a meeting
with only six or even fewer present ; but stated that there was

QUEKETT MICROSCOPICAL CLUB. 421

no less good will and friendliness among them now, and desire
to help and welcome new-comers. He felt it had been a great
advantage to himself to belong to the Club.

The chairman then proposed a rhyming " toast," wishing
" Long life to the Club," and, at his request, the members rose in
a body and " made the welkin ring " in their concurrence with
the sentiment he had so deftly expressed.

To wind up a very pleasant evening, Dr. S pitta exhibited
upon the screen a series of lantern views of natural objects,
beautifully nature-coloured. Many of various flowers were
wonderful productions, with the colours unbelievably soft and
lifelike, and some of the insects were not less successful. The
meeting then broke up, many staying, however, to examine more
leisurely Mr. Watson Baker's unique specimens.

Unfortunately too late to be read at the meeting, a Marconi-
gram arrived from the late hon. secretary, Mr. W. B. Stokes, at
Montreal : " Congratulations five hundredth meeting." (Signed)
Stokes.

422

OBITUARY NOTICE.

MORDECAI CUBITT COOKE, M.A., LL.D., A.L.S.

(Born July 12th, 1825; died November 12th, 1914.)

It is with feelings of great regret we have to record the death, in
his ninetieth year, of Dr. M. C. Cooke, the " Father of the Club,"
which took place on November 12th at his residence in Southsea.

Dr. Cooke was born in 1825 at the village of Horning in
Norfolk, where his parents kept a general shop. From an early-
age he was dependent upon his own resources, und was in turn
employed as draper's assistant, teacher in a National school and
lawyer's clerk. As an assistant in the Indian Museum he at
last found congenial occupation, and when that institution was
abolished spent some time at the South Kensington Museum, in
the Mycological Department. He afterwards joined the Her-
barium at the Royal Botanic Gardens, Kew, and was for twelve
years (1880-92) in charge of the Cryptogamic Department ; in
the latter year he retired on a pension.

During this time he incorporated his own herbarium, con-
taining 46,000 specimens, with the existing collection at Kew,
as well as the collection of fungi presented to Kew by the
Rev. M. J. Berkeley. His figures of fungi, mostly coloured and
numbering 25,000 plates, are also at Kew.

His first important work was the Handbook of British Fungi,
in two volumes, published in 1871, followed by Mycogra'phia, or,
coloured figures of fungi from all parts of the world, 113 plates ;
Handbook of Australian Fungi ; and Illustrations of British
Fungi, 1,200 coloured plates. In addition to the above, over
300 articles on mycological subjects are credited to Dr. Cooke by
Lindau and Sydow ; for a period of fifteen years he also edited
Grevillea, a journal devoted to cryptogamic botany.

After his retirement in 1892 Dr. Cooke retained his interest in
fungi, and until 1904 attended the annual fungus foray of the
Essex Field Club. Recently his eyesight failed, though his mind
remained keen and active. He was honorary M.A. of Yale, and

OBITUARY NOTICE. 423

LL.D., and in 1903 he had the honour of being awarded the
gold medal of the Linnean Society.

In addition to his scientific publications, he was the author
and editor of a number of popular books in Natural History, and
was at the time associated with the publisher of Hardwicke's
Science Gossip, of which journal he was editor from its beginning
in 1865 until December 1871.

In the Journal of the Q.M.C. for November 1899 will be found
" Early Memories of the Q.M.C," a short paper contributed by
Dr. Cooke on the early history of the Club. Dr. Cooke was one
of the eleven members who attended the preliminary meeting
held on June 14th, 1865, and the meeting on July 7th, when
the Q.M.C. originated, and he was then elected one of its
first Vice-Presidents. He was President in 1882 and 1883,
and was elected an honorary member in 1893. He was always
a very active spirit at committees, meetings and excursions as
long as he attended ; his last recorded attendance was in May
1900.

Many of us will recall that our first excursions into the fairy-
land of science were made under the guiding hand of Dr. M. C.
Cooke.

424

Table for the Conversion of English and Metrical
Linear Measures; Yard and Metre at same Temperature.

1 -i-

2

mm.

1 +

A 4

1 -r-

f l

1 +

A

H

A*

12-70

27

940

53

479

79

321

125

203

*>

o

8-4 6

28

907

54

470

80

317

130

195

4

6-35

29

876

55

462

81

313

135

188

5

5-08

30

846

56

453

82

310

140

181

6

4-23

31

819

57

445

83

306

i 145

175

7

3-63

32

794

58

438

84

802

150

169

8

3-17

33

76!)

59

430

85

299

155

164

9

2-82

34

747

60

423

86

295

160

159

10

2-54

725

61

416

87

292

165

1 54

11

2-31

3(5

705

62

410

88

289

170

149

12

212

37

686

63

403

S!)

285

175

145

13

1-95

38

668

64

397

90

282'

180

141

14

1-81

31)

651

65

391

91

279

185

137

15

1-69

40

635

66

385

92

276

190

1 34

16

1-59

41

619

67

379

93

273

195

130

17

1-49

42

605

68

373

94

270

200

127

18

1-41

43

591

69

368

95

267

205

124

19

1-34

44

577

70

363

96

265

210

121

20

1-27

45

564

71

358

97

262

215

118

21

1-21

-if ;

552

72

353

98

259

220

115

22

115

47

540

73

348

99

256

225

113

23

1-10

48

529

74

343

100

254

230

110

24

1-06

49

518

75

339

105

242

; 235

108

25

1-02

50

508

76

334

110

231

i 240

106

A 4

51

498

77

330

i 115

221

i 245

104

26

977

52

488

78

326

120

212

! 250

102

As the measurements of many microscopical objects are given in
fractions of an inch in English literature, and in metrical measure in
foreign works, the above table has been drawn up to facilitate com-
parison. Its use is obvious. Examples : l/7th inch = 3 63 mm., l/58th inch
= 438 ft, or -438 mm. For fractions smaller than 1 /250th inch that portion
of the table between the figures 26 and 99 may be used by cutting off
the last figure for hundredths, and the two last figures for thousandths.
Examples: 1 /270th inch = 94*0 p, or -0940 mm.; l/7900th inch = 321 p,
or "00321 mm. When that portion of the table between the figures 100
and 250 is used it is only necessary to cut off the last figure for thousandths
and the two last figures for ten thousandths. Examples : l/1350th inch
= 18-8 p, or -0188 mm., l/16500th inch = 1-54 p, or -00154 ram. The
conversion of millimetres into fractions of an inch is performed in the same
manner; thus, 529 p or -529 mm. = l/48th inch; 39-7 p or -0397 mm.
= l/640th inch ; 2-62 p or -00262 mm. = l/9700th inch ; 1-04 p or -00104
mm. = l/21500th inch; -977 p or -000977 mm. = l/26000th inch, and
so on. E. M. N.

425

THE EARLY HISTORY OF THE QUEKETT MICRO-
SCOPICAL CLUB.

By R. T. Lewis, F.RM.S.

The Quekett Microscopical Club this year attains its Jubilee,
and, as no doubt many of its present members are unacquainted
with its early history, it has been thought that some account of
this would be of interest.

Hardwicke's Science Gossip was started in January 1865, and
in the May number of that periodical a letter appeared from
Mr. W. Gibson, suggesting that a Society for Amateur Micro-
scopists on similar lines to those of the Society of Amateur
Botanists (of which he was a member) would be desirable, as
being a means of bringing together those having similar tastes,
who could meet to discuss difficulties and assist one another in a
manner not provided for by the existing Society. Monthly meet-
ings and a small subscription were proposed, and persons interested
in the matter were invited to co-operate. The Editor of Science
Gossip gladly inserted this communication, and, being himself the
President of the Society of Amateur Botanists at the time,,
entered fully into the project, and together with Mr. W. M
Bywater and Thomas Ketteringham met at the house of the
former in Hanover Square, and having discussed its feasibility,
decided that such a society should be established, and should be
named " The Quekett Club " after the name of the distinguished
Professor of Histology * who had died :a short time previously,

* John Thomas Quekett, b. 1815. In 1856 he succeeded Prof. Owen as
Conservator of the Hunterian Museum, and was appointed Professor of
Histology, which post he held until his death. He was elected F.R.S. in
1860, and died in 1861. He was Secretary of the Microscopical Society of
London for nineteen years. His Practical Treatise on the Use of the Micro-
scope is, or was, well known.

Journ. Q. M. C, Series II. No 76. 30

426 R. T. LEWIS ON THE EARLY HISTORY OF THE

A meeting of twelve gentlemen known to be interested in the
microscope was therefore called, and took place on June 14th,
1865, at the offices of Mr. Robert Hardwicke in Piccadilly. This
meeting was attended by eleven out of the twelve summoned, the
chair was taken by Mr; M. C. Cooke, and on the motion of Mr.
W. Gibson it was unanimously resolved that such a Club should
be formed, and on the motion of Mr. E. Jaques it was also
unanimously decided that a provisional Committee of five gentle-
men, with Mr. Bywater as Secretary, should be appointed, and
charged with the duty of deciding as to the best means of carrying
out the object in view, and to report the result of their delibera-
tions to an adjourned meeting to be held on July 7th. This
meeting, which was held at St. Martin's National Schools, was
attended by about sixty gentlemen, when four suggestions made
by the Committee were discussed and severally put to the meeting,
it being eventually decided :

(1) That the new society should be called the Quekett
Microscopical Club.

(2) That the meetings be held on the fourth Friday of every
month.

(3) That the subscription be 10s. per annum, payable in
advance, and be considered due as from July 1st, 1865.

(4) That the business of the Club be conducted by a President,
two Vice-Presidents, twelve Members of Committee, a Secretary
and a Treasurer.

It was further decided that the provisional Committee should
be empowered to carry on the business of the Club and to receive
subscriptions until the appointment of regular officers had been
duly made ; the meeting was then adjourned until August 4th,
1865. At the adjourned meeting, which was also held at
St. Martin's Schools, a series of eleven By-laws were passed,
Dr. Edwin Lankester was elected the first President of the Club,
with Messrs. M. C. Cooke and P. le Neve Foster as Vice-Presi-
dents, Mr. Robert Hardwicke as Treasurer, Mr. W. M. Bywater

QUEKETT MICROSCOPICAL CLUB. 427

Secretary, and twelve members to serve on the Committee.

The first Ordinary Meeting was held on August 25th, 1865, in

the rooms at 32, Sackville Street, when the President took

the chair and gave an interesting inaugural address, and the

Quekett Microscopical Club was thus fairly started on what has

proved to be a successful career. The rapid increase in the

number of members soon made it apparent that the room in

Sackville Street was not large enough for the purpose, and the

Eighth Ordinary Meeting was held in the Library of University

College, kindly placed at the disposal of the Club by the Council

of the College, through whose courtesy the meetings continued to

be held there until 1889. Dr. Lankester was succeeded in the

Presidency by Mr. Ernest Hart, and it was in October 1866

that the suggestion was made that the proceedings of the

Club were now of sufficient importance to deserve some record,

and in the following month reports were taken by Mr. R. T.

Lewis, who has carried out this duty to the present time. The

earlier papers read at the meetings were in some instances

published in the Microscopical Journal or in Science Gossip, but

they were subsequently printed in the Journal of the Club,

which was commenced in 1868 under the editorship of Mr. W.

Hislop.

The first Soiree of the Club was held at University College
on January 4th, 1867, and notwithstanding a heavy fall of
snow and frost of exceptional severity, in consequence of
which vehicles were only to be obtained at a high premium,
it was attended by a large number of members and their
friends, and was deemed to have been a decided success.
Profiting, however, by the experience gained on this occasion,
future Soirees were held somewhat later in the year. The
number of members at the end of the second year of the
Club's existence was 273. Eleven Field Excursions took place,
the Cabinet contained 260 slides, and an "Exchange of Slides
Committee" was appointed.

428 R. T. LEWIS ON THE EARLY HISTORY OF THE

Mr. Arthur E. Durham was the third President, and held the
office for two years, during which period the Journal of the Club
made its first appearance, the extra meetings on the second
Friday in each month were commenced, and the first dinner took
place at Leatherhead, Mr. Suffolk's classes* were restarted, and
the number of members was reported as having reached 512. It
was towards the beginning of 1868 that a member of the Com-
mittee began to agitate for the admission of women as members,
a proposal strongly deprecated by his colleagues as being sub-
versive of the interests of the Club. This gave rise to considerable
opposition from the members generally, and much merriment
was created by the circulation of sketches by Mr. Suffolk and
Mr. Lewis, and by the issue of a skit purporting to be the
report of a meeting held two years ahead and embodying most
of the objections to the scheme. It was, however, formally-
proposed at the Ordinary Meeting in March 1868, Dr. Tilbury
Fox in the chair, but on the resolution being put it found only
two supporters, and was therefore negatived by an overwhelming
majority.

At the Annual Meeting in 1869 Mr. P. le Neve Foster suc-
ceeded Mr. Durham as President, but the latter took the chair
at the November meeting, when a handsome testimonial was
presented to Mr. Bywater on his retirement from the position
of Secretary, the duties of that office having been taken over
by Mr. T. C. White. In 1870 the members had increased so
much that it became necessary to reduce the number of invitation
tickets issued for the Annual Soiree, a charge being made for

* Mr. W. T. Suffolk conducted a class for beginners during the winter
of 1865-6 in a room at the Society of Arts, kindly placed at his disposal
for the purpose by Mr. P. le Neve Foster. At this he gave useful and
practical information on the management of the microscope, the mounting
of objects, etc. The class was suspended during the summer months, but
was resumed during the winter of 1866-7, and was fairly well attended
but as there is no later mention of it, I infer that it was not again started,,
but occasional demonstrations at the Gossip Meetings seem to have
taken its place.

QUEKETT MICROSCOPICAL CLUB. 429

those wanted in excess, the sale of which realised =5 7s. Qd.,
a,nd this was given as a donation to University College Hospital.
The next four Presidents, Dr. Lionel S. Beale, Dr. Robert
Braithwaite, Dr. John Matthews and Mr. Henry Lee, each held
the office for two years. At the Annual Meeting in 1873
Mr. White retired and was succeeded by Mr. J. E. Ingpen, with
Mr. E. Marks as Assistant Secretary. Mr. Robert Hardwicke,
the first Treasurer of the Club, died in 1875, and was succeeded
in the office by Mr. F. W. Gay. In 1878 Prof. T. H. Huxley
was elected President, being followed by Dr. Spencer Cobbold in
1879, Mr. T. C. White in 1880 and 1881, Dr. M. C. Cooke in
1882 and 1883, Dr. W. B. Carpenter in 1884, Mr. A. D. Michael
in 1885, 1886 and 1887, and Mr. B. T. Lowne in 1888-9. The
<3ate of the Annual Meeting was altered to the last Friday in
February in 1888.

The last meeting in the Library of University College was
held on February 22nd, 1889, but the Council of the College
generously placed their Mathematical Theatre at the disposal
of the Club. This room, however, was found unsuited to their
purpose, and arrangements were made for removal to 20, Hanover
Square. This necessitated a change of the meeting nights to
first and third Fridays, and no Ordinary Meetings were after-
wards held in July and August. The history of the Club during
the last twenty-four years need not be recorded here, as all
particulars are to be found in the reports, and are doubtless
well known to the majority of the members. Briefly, however,
since its commencement in 1855, it has had twenty-three Presi-
dents, seven Secretaries, and has published sixteen volumes of its
Journal.

Of the original members but few are now left, and of those
who joined in the first year only two now are seen at the
meetings. Mr. W. Gibson, whose suggestion led to the Club's
formation, does not appear to have contributed to the pro-
ceedings, though he continued to be a member for eighteen

430 R. T. LEWIS, EARLY HISTORY OF QUEKETT MICROSCOPICAL CLUB,

years. Mr. M. C. Cooke, who took the chair at the preliminary
meetings, was elected an honorary member in 1893, and con-
tinued to take a lively interest in the well-being of the Club up
to the time of his death, which occurred in his ninetieth year,
only a few months ago.

Journ. Qutkett Microscopical Club, Str. 2, Vol. XJL, No. 7(5, April 1915.

431

A NEW COPEPOD FOUND IN WATER FROM HOLLOWS

ON TREE TRUNKS.

By D. J. Scourfield, F.Z.S., F.R.M.S.
{Read November 24th, 1914.)

Plates 24 and 25.

The search for plants and animals in unusual and unlikely
places is always interesting, and may be sometimes richly re-
warded. As a case in point, and the one which led directly to the
discovery of the new species of Copepod that I wish to describe
in this paper, we may consider what has been done in the
elucidation of the fauna living in the little natural cups formed
by the bases of the leaves of plants belonging to the Order
Bromeliaceae, i.e. the order to which the pine-apple belongs.

It was in 1879 that the celebrated naturalist Fritz Miiller,
who was at that time associated with the National Museum in
Rio de Janeiro, called attention to the fact that the water con-
tained in the little cups just referred to was tenanted by various
forms of animal life. In particular he described a new Ostracod,
representing a new genus, Elpidium bromeliarum, which occurred
almost constantly in association with the Bromeliaceous plants
in the forests of Brazil, and strangely enough was to be found
in no other situation (5, 6, and 7).

Since that date a number of other investigators have from
time to time examined these little collections of water retained
by the leaves of Bromeliaceous plants, and I may here mention
that soon after I became acquainted with the work of Fritz
Miiller I commenced to look for Entomostraca in these situa-
tions at the Royal Botanic Gardens, Regent's Park, and at Kew.
My curiosity was gratified by finding the remarkable blind
Copepod, Belisarius viguieri, which had not previously been
found in this country.* In recent years still more attention

* Kecorded and figured in Joum. Q. M. C, vol. viii., November 1903,
p. 539, and vol. ix., April 1904, PI. 2 (15). For further notes on this species
see also The Wild Fauna and Flora of the Royal Botanic Gardens, Kew,
p. 20 (16).

432 D. J. SCOURFIELD OX A NEW COPEPOD FOUND IN

has been given to the subject owing to the endeavour to discover
the life-histories of mosquitoes and other insects supposed to be
connected with the dissemination of tropical diseases. Last year
a very elaborate paper was published by Picado (8), in which
he gives details of the facts previously elucidated, and of his
own work on this subject in Costa Rica. It appears that no
less than about 250 species of animals have been found living
in this peculiar environment, 49 being new to science. They
belong to almost all groups of Invertebrates, but naturally
insects and their larvae predominate. The Amphibia are also
represented. A very full account of this paper has been recently
published by H. Scott in the Zoologist (12).

When once this peculiar habitat had been pointed out, it was
natural that somewhat similar situations should be searched, and
records have indeed been made of animals found living in the
pitchers of Pitcher-plants and Sarracenias, the holes occurring
occasionally in bamboos, the tops of palm trees, and in various
other places.

It occurred to me that perhaps the little collections of water
which are sometimes to be found in the hollows and crevices
on the trunks and exposed roots of trees might possibly be
inhabited by some member or members of the Entomostraca,
the group in which I am more particularly interested. This
proved to be the case ; at least I am now able to report that
on several occasions I have found the minute Copepod about
to be described in such little reservoirs of water on trees in
Epping Forest. Up to the present it has been found nowhere
else, and, on the other hand, I have never found any other
species of Entomostraca in the same places.

The new species evidently belongs to the Harpacticid genus
Moravia T. and A. Scott, and I propose to call it M. arboricola
on account of its tree-dwelling habit.

The genus Moravia is very closely allied to the well-known
genus Canthocamptus, and is, in fact, even now included in the
latter by some authors. It was instituted by T. and A. Scott in
1893 (14) for a species found in Loch Morar, in Scotland, which
they named M. andevson-smithi, believing it to be new, but
which subsequently proved to be identical with C anthocamptus
brevipes Sars, described thirty years previously (11). A month
or two later in the same year, 1893, Mrazek described as new

WATER FROM HOLLOWS ON TREE TRUNKS. 433

the same species, placing it with two others which were really
new to science, in a new genus, Ophiocamptus, thus showing that
he also recognised the necessity of separating Sars's C. brevipes
-and closely allied forms from the old genus C anthocamptus (4).

The characteristics of the genus Moraria are chiefly as
follows : Body very elongated, almost vermiform. Rostrum
broad. First antennae seven-jointed. First four pairs of feet
with three-jointed outer and two-jointed inner branches. Inner
branches of first pair of feet only a little shorter than the outer
branches, with the basal rather longer than the terminal joint.
Inner branches of the second, third, and fourth pairs of feet
only a little longer than the first joint, or at most only as long
as the first two joints of the outer branches. Furca well de-
veloped, each branch tapering considerably from base to tip, and
usually (? always) furnished with a strong longitudinal chitinous
ridge on the dorsal surface.

So far as I can ascertain, eight species of Moraria have hitherto
been described and two others referred to, but not described.
They are as follows :

M. brevipes (G. 0. Sars), 1863 = C anthocamptus brevipes G. 0.
Sars, 1863 (11); M. anderson-smithi T. and A. Scott,
1893 (14) ; Ophiocamptus sarsi Mrazek, 1893 (4).

M. mrdzeki T. Scott, 1903 (13), new name only = Ophio-
camptus brevipes Mrazek, 1893 (4).

M. poppei (Mrazek), 1893 (4) = 0. poppei Mrazek, 1893 (4).

M. muscicola (Richters), 1900 (9) = 0. muscicola Richters,
1900 (9).

M. schmeili van Douwe, 1903 (3).

M. mongolica (Daday), 1906 (1 and 2) = 0. mongolicus Daday,
1906 (1 and 2).

M. wolfi Richters, 1907 (10).

M. quadrispinosa Richters, 1907 (10).

M. sp. 1 Richters, 1907 (10).

M. sp. 2 Richters, 1907 (10).

Most, if not all, of the above have been found living in wet
-or damp mosses ; some, in fact, have hitherto been found in no
other situations. Only the first three have been found in the
British Isles.

434 D. J. SCOURFIELD ON A NEW COPEPOD FOUND IN

Moraria arboricola sp. nov.

Female. Body (fig. 1) long and vermiform, divided into nine
free segments, the first being the longest and the sixth (first-
abdominal) the second in length. Rostrum broad. Eye red or
brownish red, moderately large as a rule, but rather variable in
size and in outline. Dorsal plate on carapace rather variable
in shape, usually more or less rectangular with rounded angles r
slightly broader in front than behind. Posterior margins of all-
segments smooth on dorsal surface. On ventral surface abdominal
segments (fig. 16) armed as follows: 1st, with two widely
separated groups of about five teeth ; 2nd, with a row of teeth
from one-third to half width of segment, sometimes with central
teeth missing, thus leaving two isolated groups; 3rd, with a row
extending almost across segment ; 4th (last), with a row com-
pletely across segment and a little way round sides, except for
the slight interruption caused by the posterior median notch.
Anal plate or operculum (see fig. 15) more or less semicircular^,
with smooth but slightly wavy edge, and with faint dark and
light bands radiating towards the edge, showing probably that
the plate is very slightly corrugated.

In the stage before the adult the edge of the anal plate is not
smooth, but furnished with a few very minute teeth, widely but
somewhat irregularly spaced (fig. 13). In the still earlier stages
the teeth are rather larger (fig. 12). The presence of teeth on
the anal plate in the young stages of M. brevipes, which also
has smooth edges in the adult, has been noted by Mrazek (4).

Branches of furca (figs. 14 and 15) moderately long and taper-
ing considerably, with a prominent chitinous ridge on the dorsal
surface, ending posteriorly in a blunt tooth from the base of
which springs a spine directed upwards. Outer edges armed
with two strong spines, the proximal with a minute accessory
spine at its base. Inner edges with two curved rows of minute
teeth, terminating dorsally in little teeth on the chitinous plate.
Posterior edges with a row of teeth on the ventral surface,
covering bases of terminal setae. Terminal setae usually quite
smooth, three on each furcal lobe, inner very small, outer not
quite half the length of the median, which again is about half
the body length. The outer and median setae, especially the
latter, somewhat bulbous at the base.

WATER FROM HOLLOWS ON TREE TRUNKS. 435

First antennae (fig. 2) rather short and seven-jointed, with the
olfactory seta, on the fourth joint reaching only to about the
middle of the last joint. Second antennae of the usual type
with the accessory branch (fig. 3) very small, one-jointed, bearing
three setae at the tip. First pair of feet (fig. 4) small, with
three-jointed outer and two-jointed inner branches. Inner
branch not quite so long as outer, with one of the two terminal
setae extremely long and curved at the tip. Second, third, and
fourth pairs of feet (fig. 6) very similar to one another with the
three-jointed outer branches larger than in the feet of the first
pair, but with the two-jointed inner branches smaller, being only
a little longer than the basal joints of the outer branches. The
second joints of the inner branches of the second and third pairs
of feet carry three terminal spines, the corresponding joint of the
fourth pair only two. Fifth feet (fig. 8) consisting of two joints,
the basal being extended on the inner side considerably beyond
the broadly ovate second joint. Inner part of basal joint armed
with six spines somewhat flattened, with rounded tips of the
type found in M. brevipes Sars, but not quite so broad or blunt.
The fourth and fifth spines from the inner edge arise from a
little sub-rectangular projection which has the appearance of a
pseudo-joint. A finely pointed spine projecting outwards arises
as usual from the lower corner of the outer edge of the joint.
The second joint armed with four spines, the innermost being
of the same type as those on the basal joint, and the other
three being finely pointed and not flattened. The median of
these three turns outwards across the outer spine. There is a
little thorn on the inner edge of this joint just above the inner-
most spine. None of the spines on the fifth feet are plumose,
but a single barb usually occurs on the fifth and sixth from
the inner edge, as indicated in fig. 8. Earlier stages of the fifth
feet are shown in figs. 10 and 11.

Eeceptaculum seminis (fig. 18), lying immediately behind and
usually covered by the fifth feet, somewhat complicated in
structure, consisting apparently of two lateral highly chitinised
convoluted chambers or tubes and a median membranous or
muscular cavity, the latter sometimes rhythmically contracted
and expanded by two lateral muscles, thus forming for a time
a kind of pulsating organ.

Chitinous integument of body and furca almost everywhere

436 D. J. SCOURFIELD ON A NEW C0PEP0D FOUND IN

covered with minute pits only readily noticeable under a 1/1 2th in.
objective (see figs. 14, 15, 16 and 17). Dorsal surface of most
of the thoracic and abdominal segments with lines of excessively
minute teeth arranged in various ways characteristic of the
different segments, often giving the impression of a series of
scales (fig. 17).

Eggs much elongated while in the body, only one or two on
either side, forming two lateral lines extending sometimes from
the second free thoracic to the last abdominal segment. As no
ovisac has yet been observed, it may be that the eggs are
deposited upon extrusion and not carried about.*

Length without terminal setae, l/50th in. to l/40th in.

Male. Very similar to female in general appearance, but body
divided into ten free segments, the first longest and the seventh
to tenth next in length and sub-equal. Posterior margins of
abdominal segments armed on ventral surface as follows : 1st,
with two widely separated groups of two spines each situated
on a slight prominence forming rudimentary sixth feet ; 2nd and
3rd, with a row of teeth about half the width of the segment ;
4th and 5th, with a row across whole width of segment. Anal
plate as in female, also furcal lobes and terminal setae, except
that the two little curved rows of teeth on the inner sides of
the furca are not so well developed. The edge of the anal plate
is toothed in the young stages as in the female.

First antennae modified in the usual way with no very
characteristic features. First four pairs of feet almost exactly
as in female except that the inner branches of the second, third
and fourth pairs are larger and specially modified as follows :
2nd (fig. 20), with a thick slightly curved process (? enlarged
spine) projecting downwards from the anterior face of the basal
joint and probably forming with the second joint a pincer like
apparatus; 3rd (fig. 21), with second joint carrying two strong
terminal setae, one of which is about a third the length of the
other and shaped like the blade of a knife, and the first joint
bearing a very large trailing spine curved towards the base ;
4th (fig. 7), with both joints leaf-like, the second having a
curiously twisted little spine on the lower outer margin. Fifth
feet (fig. 9) simpler than in female, the slightly extended part
of the basal joint with only two short spines, the second joint

* See note on p. 440.

WATER FROM HOLLOWS ON TREE TRUNKS. 437

of a more elongated and rectangular shape with a spine arising
from near the base on the inner edge, and four spines from the
distal edge, the third of which from the inner side turns outwards
across the outer spine. None of the spines are of the flattened
blunt type present on the fifth foot of the female.

The spermatophore (fig. 19) is flask or retort-shaped with very
thick walls, the outlet tube being embedded for a part of its
length in a mass of cementing material.*

Length without terminal setae, about l/50th in.

As regards the habits of M. arboricola not very much can be
said. They are not very good swimmers, their movements in the
open water being best described, perhaps, as an active wriggling
assisted by the beating of the feet rather than as true swimming
produced chiefly by the action of the feet. On the whole they
seem to prefer moving downwards more than upwards when free
from support. They can, however, cling very strongly even to
glass, and often in this way travel about the sides of the vessel in
which they are kept. Very often I have found that they have
clung to the inside of the pipette whilst being transferred from a
bottle to the live-box. When placed in a watch-glass I have noticed
on several occasions that a tap on the glass had the effect of suddenly
stopping their movements just as if they were feigning death.

As already mentioned, M. arboricola has only been found in
little hollows on tree trunks in Epping Forest, and so far only
in the Theydon Bois and High Beech districts, f The first
specimens were found in 1904 near Theydon Bois, and since that
date the species has been obtained many times either actually
living in the water and sediment or developing out of the black
earthy deposit taken from dry hollows and placed in water. It
has happened on several occasions that no trace of the animals
could be found in the first instance, but that after several weeks,.

* This peculiar mass can be seen in the same relative position while the
spermatophore is still within the body of the male. It seems therefore to
be a constant character and not merely a temporary feature produced at
the time of attachment to the female.

t The fact that so many of the Epping Forest trees have been pollarded
in bygone times has had the effect of largely increasing the number of
cavities and hollows on their heads and trunks in which water can
accumulate in wet weather, thus rendering the district a particularly
favourable one for the study of the fauna and flora of such a peculiar
environment. The systematic investigation of this fauna and flora is much
to be desired, and could scarcely fail to vield valuable results.

438 D. J. SCOURFIELD ON A NEW COPEPOD FOUND IN

or even a month or two, specimens have begun to appear. From
the fact that the females have not been observed carrying ovisacs *
it seems possible that the eggs are dropped into the sediment to
lie dormant for a time, or even to be dried up and so perhaps
blown about by the wind. This might account for their distribu-
tion from one tree to another, although it is very probable that
insects, of which a number of forms occur in the same situations,
may also be a means of dispersal. In this connection and also in
relation to their peculiar habitat the wonderful vitality of the
animals may play an important role. They seem capable of
living for a very long time in quite small quantities of water
and with scarcely any food. On one occasion specimens continued
in evidence for four and a half years in a 3-in. x 1-in. glass tube
in which the collection had been brought home. The tube con-
tained nothing in the way of food, except the very innutritious-
looking original sediment, and nothing was added during the
whole time but a little clean water. Individual specimens, too,
have been kept for months in very small tubes with only the
merest trace of sediment and have remained perfectly active.
Such powers of endurance must evidently be of the greatest
value to them in their natural surroundings.

Literature Referred to.

1. Daday, E. von. Edesvizi mikroskopi allatok mongoliabol.

Math. Termt. Ert., Vol. 24, 1906, pp. 34-77.

2. Daday, E. von. Beitrage zur Kenntnis der Mikrofauna des

Kossogol-Beckens in der Nordwestlichen Mongolei. Math.
Nat. Berichte aus Ungarn, Vol. 26, 1913, pp. 274-360.

3. Douwe, C. van. Zur Kenntniss der Sussuasser-Harpacticiden

Deutschlands. Zool. Jahrbucher. A bt. fiir Systematize, etc.,
Vol. 18, 1903, pp. 383-400.

4. Mrazek, A. Beitrag zur Kenntniss der Harpacticiden fauna

des Siisswassers. Zool. Jahrbucher. Abt. f. Systematic,
etc., Vol. 7, 1893.

5. Muller, F. Descripgao do Elpidium bromeliarum crustaceo

da familia dos Cythei icleos. Arch. Museu National do
Rio de Janeiro, Vol. 4, 1879, pp. 27-34.

6. Muller, F. Phryganiden-Studien. 3. Wasscrthiere in den

Wipfeln des Waldes. Kosmos, Vol. 4, 1879, pp. 390 392.

* See note on p. 440.

WATER FROM HOLLOWS ON TREE TRUNKS. 439

7. Muller, F. Wasserthiere in Baumwipfeln. Elpidium

bromeliarum. Kosmos, Vol. 6, 1880, pp. 386-388.

8. Picado, C. Les Bromeliacees epiphytes, considerees comme

milieu biologique. Bull. Scientifique de la France et de
la Belgique, Vol. 47, 1913, pp. 215-360.

9. Richters, F. Bfitrage zur Kenntnis der Fauna der

Umgegend von Frankfurt a. M., III. Ophiocamptus
muscicola n. sp., ein moosbewohnender Copepode. Bericht
der Senckenbergischen N aturforschenden Gesellschaft, 1900,
pp. 36-39 (also further notes in the same publication,
1902, pp. 6-7).

10. Richters, F. Die Fauna der Moosrasen des Gaussbergs und

einiger siidlicher Inseln. Deutsche Slid-polar Expedition,
1901-1903, Vol. 9, 1907.

11. Sars, G. O. Oversigt af de indenlandske Ferskvands Cope-

poder. Vidensk.-Selsk. i Christiania Forhandl. for 1862
(Aftr.), 1863, p. 24.

12. Scott, H. The Fauna of "Reservoir-plants." Zoologist,

Vol. 18, 1914, pp. 183-195.

13. Scott, T. Some Observations on British Freshwater Har-

pacticids. Annals and Magazine Nat. Hist., Series 7,
Vol. 11, 1903, pp. 185-196/

14. Scott, T. and A. On some new or rare Scottish Entomo-

straca. Annals and Magazine Nat. Hist., Series 6,
Vol. 11, 1893, pp. 210-215.

15. Scourfield, D. J. Synopsis of the known species of British

Freshwater Entomostraca, Part II. and Part III. (Plate).
Journal Quekett Micro. Club, Series 2, Vol. 8, 1903,
p. 539, and Vol. 9, 1904, p. 44.

16. Scourfield, D. J. The Wild Fauna and Flora of the Royal

Botanic Gardens, Kew. Crustacea, Entomostraca.
Bulletin of Miscellaneous Information, Additional Series V.
(Royal Botanic Gardens, Kew), 1906, pp. 14-20.

Explanation of Plates 24 and 25.

Moraria arboricola sp. nov.

Fig. 1. Dorsal view , x 200.
,, 2. First antenna ? , x 700.
,, 3. Accessory branch of second antenna

55
55

440 D. J. SCOURFIELD ON A NEW COPEPOD.

Fig. 4. First foot ? , x 6C0.

5. Seta on inner angle of basal joint of first foot <$ .

6. Fourth foot ?, x 600.

7. Inner branch of fourth foot J 1 , x 1000.
8. Fifth foot ?, x 1000.

9. ,, S, x 700.

10. young ? (antepenultimate stage).

11. $ (penultimate stage).

12. Anal plate, young (three stages before adult).

13. (penultimate stage).

14. Last abdominal segment and furca from side ?/x 700,

15. ,, ,, dorsal view ? , x 700,

16. 3 ,, segments ,, ventral view (some-
what flattened and contracted), x 350.

17. First and second abdominal segments, dorsal view ? y
X 350.

18. Receptaculum seminis $, x 900.

19. Spermatophore, x 400.

20. Inner branch of second foot $ (from left side), x 500.

21. third <?, x 500.

5>

J)
))
>>

55

55

Note added April 1915.

A single individual of M. arboricola has now been seen carrying
an ovisac containing four eggs, the latter being almost perfect
spheres l/500th inch in diameter. The ovisac itself was very
delicate and soon became detached, and also separated into two
parts, each containing two eggs, by the movements of the animal
when lightly held in the live-box.

Nauplii in various stages have also been seen. The earlier
forms exhibit a somewhat elaborate structure on the back, con-
sisting of three pairs of papillae with pointed tips lying between
two strong lateral thorns. Whether this is characteristic of the
species or not is unknown.

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., N: 76, Ap 1915.

Journ.Q.M

Sep. 2 ai,P1.24.

Scourfield del. ad

-Newman lith.

Jour-

Ser.2 25.

\

Wrv^

!0

(J

.

j'/fVl/Vi'Wi -YJCWW

ScourfielddeLadnat. West,Newn u

kria arborieola sp.nc

441

SOME DETAILS IN THE ANATOMY OF THE RAT-FLEA,
CERATOPHYLLUS FASCIATUS BOSC.

By Prof. E. A. Minchin, M.A., Hon. Ph.D., F.R.S.

{Bead January 2Qth, 1915.)

Plates 26-32.

During the past five years I have been engaged, in collaboration
with a friend, upon investigations, recently published,* into the
development of the rat-trypanosome in its invertebrate host the
rat-flea (Ceratophyllus fasciatus). In the course of this investi-
gation we have dissected and examined some 1,700 fleas ; and
although these dissections were not undertaken with the
primary object of studying the anatomy of the flea, but only
with the intention of extracting and examining those organs of
the flea likely to contain stages of the trypanosome, it goes
without saying that we have not pulled so many fleas to pieces
without gaining some insight into the structure of the insect,
and it seemed to me worth while to study some anatomical points
of structure in more detail and in special preparations. Some
parts of the flea are very interesting as regards their structural
relations and make very beautiful microscopic preparations which
can be mounted with very little trouble. I thought it might
interest the members of the Club if I laid before them a brief
account of some points of flea-anatomy seen by the way obiter
visa, if I may use the expression,

Before describing these observations, I wish it to be clearly
understood that this paper does not pretend to give a complete
anatomical description either of the flea as a whole or even of
the systems of organs that are dealt with. There are many
structural details which could only be made out by sections, and
I have had no leisure for the task of section-cutting, always a
difficult and laborious undertaking in the case of insects, on
account of the toughness of the chitinous cuticle, which cannot

* Minchin and Thomson, " The Rat-trypanosome, Trypanosoma lewisi,
in its Relation to the Rat-flea, Ceratophyllus fasciatus" Quarterly
Journal of Microscopical Science, Vol. LX., Part 4, 1915.

Journ. Q. M. C, Series II. No. 76. 31

442 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF

be dissolved out. I do not propose to describe any details here
which cannot be verified by an observer possessing a dissecting
microscope * and a pair of mounted dissecting needles and a
flea ! In fact the results obtained by me and set forth here are
based entirely on what may be termed " needlework."

Before proceeding to anatomical descriptions, I may give a
brief account of the technique I have employed. The flea at
liberty is, I need not say, an active and elusive insect. But
when placed on the surface of water, he is perfectly helpless, and
floats there without being able to escape and without drowning
for at least twenty-four hours, provided there is no soap in the
water ; if there is a trace of soap the cuticle of the flea is wetted
and the insect sinks and is soon drowned. (This hint may be
borne in mind as being often useful in the home.)

Having therefore caught your flea, put it on the surface of
some water and keep it until you can proceed further with your
operations. An expeditious way of catching the flea is to get
it to hop straight on to the surface of water. In doing this
remember that a flea always hops by preference away from the
source of light, never towards it.

When it is desired to dissect the flea it should be gathered off
the surface of the water with a fine forceps and placed in a drop
of physiological salt-solution (0*75 gramme sodium chloride in 100
cubic centimeters of distilled water) on an ordinary microscopical
slide, which is then placed on the stage of the dissecting
microscope.

For the dissection I use two fine needles mounted in wooden
handles. Each needle after fixing in the handle is ground down
further on an ordinary hone. One of them is ground to a fine
sharp point, the other to a flat cutting edge. For preparing the
flat-edged needle, I first take a penknife and pare the extremity
of the wooden handle on both sides so that it is shaped like an
ordinary brad-awl. I then rub the needle down on the hone in two
planes parallel to the two cuts made in the handle, checking the
process under the dissecting microscope and trying to get a
rounded cutting edge, not an edge which terminates in a straight
line like an ordinary chisel. The object of paring the wooden
handle is both to guide the hand when rubbing down the needle

* I have used in all my work a Greenough binocular dissecting
m'croscope made by Zeiss.

THE RAT-FLEA, CERATOPHYLLUS FASCIATUS BOSC. 443

on the hone, and also to distinguish the flat-edged needle from
the pointed one. When dissecting I use the pointed needle in
my left hand for holding the object, and the flat-edged needle in
my right hand for cutting. The needles should be pushed far
into the wooden handle, so that only a short length is free, other-
wise the needle is too springy and is liable to snap under
pressure.

The flea was left in the drop of salt-solution, where it is kicking
about violently and may succeed, if not watched, in getting out
on to the slide and hopping off*. It is therefore best to begin by
decapitating the flea. This can be done by holding it still with
the pointed needle and snipping off the head with the flat-edged
needle. The dissection can then be proceeded with in a manner
free from haste or anxiety.

I will describe now a method of making permanent preparations
of the organs of the flea which I have found very useful. There
is not a single detail of anatomy described in this paper which I
could not demonstrate to a sceptic in my permanent preparations *
at a moment's notice. Let us take the abdominal nervous system,
for example. The complete nervous system of the flea consists,
as in other insects, of the three sets of nerve-ganglia: (1) the
cephalic ganglion -complex, or brain, situated in the head dorsal
to the digestive tract (supra-oesophageal) ; (2) three pairs of
thoracic ganglia, corresponding to the three thoracic segments :
(3) a chain of abdominal ganglia extending into the abdomen.
Parts (2) and (3) are ventral to the digestive tract and constitute
a continuous chain of pairs of ganglia, but the two ganglia of any
given pair are fused together so as to appear like a single ganglion-
mass. Each pair of ganglia is connected with the pair next
behind or in front by a pair of stout nerves, known as " connec-
tives," and it can be plainly seen that these connectives remain
distinct in each pair, and are not fused together like the ganglion-
pairs (PI. 26). The first pair of thoracic ganglia is connected
with the brain by a pair of peri-oesophageal connectives. From
the ganglia are given off* nerves to the various organs of the body.

It is almost impossible to dissect out the brain, and to study its

structure and relations sections would be necessary. It is difficult,

but by no means impossible, to dissect out the thoracic ganglia.

Major Christophers, I. M.S., who worked for a time in my

* These preparations are now the property of the Club.

444 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF

laboratory at the Lister Institute, made some beautiful dissections
of the ventral nervous system of the flea, showing both thoracic
and abdominal ganglia in continuity. On the other hand, it is by
no means difficult to dissect out the abdominal chain in its whole
length, up to and including the large metathoracic ganglia, the
ganglia of the jumping legs. To do this the flea should be held by
the thorax with the pointed needle, while with the flat -edged needle
the abdominal segments are carefully detached and pulled off
from behind forwards successively, until only the thoracic segments
are left. If the operation has been successfully performed, and
the abdominal segments together with the contained digestive
and reproductive organs removed, the abdominal chain of ganglia
will be seen proceeding from, and adhering to, the hindmost
thoracic segment. With practice the complete severance of the
abdomen and its organs from the thorax can be effected with one
pull.

Now take another slide and place on it a cover-slip (| inch
square). Place the slide and cover-slip on the stage of the dis-
secting microscope, put a quite small drop of salt-solution on the
cover-slip, and transfer the thorax of the flea from the slide on
which it was dissected to the small drop of fluid on the cover-slip,
and there proceed with the dissection. The big metathoracic
ganglion-mass can be seen quite plainly in the hindermost part
of the thorax, with the abdominal chain of ganglia proceeding
from it. With the needles the metathoracic ganglion must be
carefully dissected out and set free from the thorax ; this operation
is not at all difficult, though it requires both skill and practice to
dissect out the first two thoracic ganglia as well, in unbroken
continuity with the rest of the ganglionic chain. If during the
dissection the cover-glass slips about on the slide, it can be fixed
quite firmly by letting a tiny drop of distilled water run in between
cover-glass and slide, but I avoid this as a rule, because it makes
it difficult to get the cover-slip off later on.

When the dissection has been completed, the fragments and
debris of the thorax should be removed and cleaned up as much
as possible, leaving the nervous system in the small drop of fluid
on the cover -slip. Now the cover-slip must be lifted carefully off
the slide and all superfluous moisture drained off it, so as to leave
the nervous system stranded on the cover-slip, as near the centre
as possible. The fluid can be drained off either by tilting the

THE RAT- FLEA, CERATOPHYLLUS FASCIATUS BOSC. 445

cover-glass and letting the salt-solution run off, or, if the nervous
system shows a tendency to run off with the fluid, by holding the
cover-glass flat and carefully mopping up all superfluity of fluid
with a small piece of filter-paper. The object to be attained is to
leave the specimen stranded on the cover-glass and to drain off as
much of the salt-solution as possible, in order that by capillary
attraction the object may be pressed against the cover-slip ; but
on no account must the fluid be allowed to dry completely. When
this has been done the cover-slip is inverted, so that the object is
on its lower side ; and then it is dropped face downwards quite
flat on to the surface of some fixative fluid.

Various fixatives can be used, but I have nearly always made
use of 5 per cent, sublimate-acetic that is to say, saturated
solution of corrosive sublimate in distilled water, 95 volumes,
mixed with glacial acetic acid, 5 volumes. When fixing the
preparation some of the fixative is put into a large watch-glass
or clock-glass and the cover-glass with the adherent object is
dropped on to it and remains floating on the surface of the
solution. In nine cases out of ten the object remains firmly
adherent to the under side of the cover-glass, if one has hit the
happy medium in draining off the fluid in which it was dissected
out. If superfluity of the salt-solution remains, the object will
come off; if it has been allowed to dry up altogether, the
preparation is ruined.

The cover-glass with the adherent organs can now be mani-
pulated just as if it was a smear, lifting the cover-slip with an
ordinary forceps and transferring it from one liquid to another.
After the preparation has been fixed in the sublimate-acetic for
some time, say from 10 minutes to an hour, it can be brought
up through successive strengths of alcohol in watch-glasses
(10 per cent., 30 per cent., 50 per cent, and 70 per cent.) to
90 per cent, alcohol, in which it should be left for a longer time
(preferably over night, or as long as is convenient) in order that
the preparation may be well hardened and the corrosive sublimate
thoroughly dissolved out. In the stronger alcohols the cover-slip
will sink, but it rests on its corners on the rounded bottom of
the watch-glass and there is no contact or pressure on the object,
which of course is on the under side of the cover-slip. It is now
apparent why square cover-slips must be used, since they rest on
their corners and can be easily picked up with the forceps :

446 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF

round cover-slips would be in contact with tbe watch-glass round
their whole edge, and be very troublesome to lift up with the
forceps or in any other way.

Sometimes the object comes away loose from the cover-slip in
the sublimate-acetic. When this annoying event takes place,,
put the cover-slip into a watch-glass and cover it with 30 per cent,
alcohol; then draw up the object from the sublimate-acetic
mixture with a glass pipette of sufficiently wide calibre and place
it on the upper surface of the cover-slip in the alcohol. Then lift
up the cover-slip carefully with a forceps, taking care the object
does not float off the cover-slip to one side or the other, but
remains stranded on the cover-slip again. Then drain off the
alcohol, invert the cover-slip, and drop it face downwards into
50 per cent, alcohol in another watch-glass. This time the
rebellious object always sticks to the cover-slip. In all cases the
cover-slips should be handled delicately while in the sublimate-
acetic or in the weak alcohols, since a too violent jerk may
dislodge them ; but I have never known an object to come loose
after it has got so far as the 70 per cent, alcohol.

I have described this method in full detail because I have
found it extremely useful for making permanent preparations
of dissections. In the flea, for example, it is very easy to dissect
out and mount in this way the entire male reproductive system,
from testes to penis, and so display every detail of it ; and since
the preparation is adherent to the cover-slip, any powers of the
microscope, even immersion lenses, can be focused on to it for
study of minute details. The principle of the method is that
cellular tissues, having been pressed firmly but gently against
the glass by capillary attraction, adhere to the glass by their
own stickiness ; and when the preparation has been well fixed
and hardened, the coagulation of the albumins glues the organs
so firmly that they cannot be detached without breaking
them. Naturally this does not apply to chitinous organs,
which are not wetted by water, and can never be made to stick
in this way.

The preparations, after having been fixed and hardened, can
be mounted unstained, or can be stained first in any way desired..
Unstained preparations are best for showing internal details of
the chitinous cuticle or skeleton ; stained preparations for
showing the cellular structure of the tissues and soft parts ; the

THE RAT-FLEA, CERATOPHYLLUS FASCIATUS BOSC. 447

one method of preparation supplements the other. For staining
an alcoholic stain is preferable, since prolonged soaking in watery
stains might produce maceration and cause the object to become
detached again from the cover-slip. I have always used Gren-
adier's alcoholic borax-carmine, in which the objects are stained
for about five minutes, and then transferred to acidulated alcohol
(0*1 per cent, hydrochloric acid in 70 per cent, alcohol), in order
to extract all the carmine stain from the cytoplasm of the cells
and leave it only in the nuclei. If the stain be not thoroughly
extracted in this way the preparation will be very opaque, and
I find it best to leave the objects in the acidulated alcohol for about
forty-eight hours, changing the fluid occasionally. I believe this
method could be improved upon, and that Mayer's alcoholic
paracarmine * would give a more transparent stain, and one
more easily extracted. Some of the well-known haematoxylin
mixtures would probably also give good results.

The stained or unstained preparations are then finished off by
passing them into absolute alcohol, then into oil of cloves or any
other of the ordinary clearing reagents, and finally into Canada
balsam. The cover- slips can be mounted over well-slides or
preferably, in my opinion on ordinary slides, with the precau-
tion of supporting the corners of the cover-slip on wax feet or in
some other way, in order that the objects may run no risk of
being crushed between slide and cover-slip.

I will now proceed to set forth some of my observations on the
anatomy of the flea, noting, as a preliminary, that all my state-
ments apply to the common rat-flea, Ceratophyllus fasciatus y
the only species I have dissected. Other species of flea may
perhaps show slight differences in some points.

It is also my pleasant duty, at this point, to express my warm
thanks to Miss Mabel Rhodes, artist at the Lister Institute, for
kindly executing the drawings of my dissections which accompany
this paper. They were all drawn with the camera lucida from
the actual preparations.

I. The Abdominal Nervous System.

The method of dissecting out the abdominal chain of nerve-
ganglia has been described above. It is one of the easiest

* For an account of these stains and how to prepare them see Bolles
Lee's well-known Vade-mecum.

448 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF

dissections if one is content to get out only the large meta-
thoracic ganglion-mass, in the thoracic series, and not to worry
about the ganglia of the first two thoracic segments, which
require very careful dissection.

A remarkable feature of the abdominal nervous system is that
it presents very marked differences in the two sexes of the flea.
These sexual differences are seen at a glance in the two figures
on PI. 26, which are drawn from two preparations to the same
scale by means of a camera lucida. At the upper end of each
figure we see the large metathoracic ganglion-mass, and at the
lower end the large hindmost or terminal ganglion-complex from
which nerves are given off to the genitalia. Between these two
larger nerve-centres at the two extremities there is a series of
smaller ganglia ; and it is easy to see that this series comprises
seven ganglia in the male and only six in the female.*

It is seen, then, that the male flea has one pair of ganglia
more in its abdominal nervous system than the female. Is this
an indication of superiority on the part of the male sex ? By
no means, rather the contrary ! In the embryonic development
of insects there are some ten or eleven pairs of abdominal ganglia,
and in the ontogenetic development, or in the phylogenetic
ovolution, of insects the tendency is for these ganglia to be
concentrated by fusion which takes place progressively from
behind forwards. In some of the Diptera the tsetse-fly, for
example, and I believe in the common house-fly also the
concentration of the nerve-ganglia has reached its maximum
possible, since the whole ventral chain is concentrated into one
large mass situated in the thorax, a mass which represents the
three pairs of thoracic ganglia plus the whole abdominal chain,
all telescoped forwards into one large ganglion-complex. In the
flea, however, the process of concentration and specialisation has
not gone so far, and is seen only at the hindmost end of the

* This curious point was discovered by Major Christophers, in his
dissections of fleas made in my laboratory. Previous to his work, I had
counted the ganglia of a female flea that I was dissecting, and had noted
that there were six small ganglia. Subsequently I made a mounted pre-
paration of the abdominal chain of a male flea, and was surprised to
observe seven small ganglia ; thinking I had made a mistake in my former
observation, I looked up my old notes and altered " six " to " seven, '
never suspecting the sexual differences which were subsequently shown to
exist.

THE RAT- FLEA, CERATOPIIYLLUS F ASCI ATI'S BOSC. 449

nervous system, in the large terminal ganglion-mass, which
represents a fusion of the most posterior ganglia. The difference
in the number of the abdominal ganglia in the two sexes of the
flea shows, therefore, that in the female the concentration has
gone one step farther than in the male, since only six abdominal
ganglia remain free in the female, but seven in the male. The
nervous system of the female has therefore reached one stage in
evolution higher in the female than in the male. Similar
differences between the sexes are known to occur also in other
insects, especially in the Hymenoptera (the order which includes
the bees, ants, and wasps), an order in which the superiority in
intelligence and in the social virtues of the female over the male
is very marked.

Besides the difference in the number of ganglia, the nervous
systems of the male and female flea differ also in the arrangement
of the nerve-stems given off from the hindmost ganglion-mass. In
the male two stout nerves are given off, which run on either side
of the " corkscrew-organ'' (see p. 454), and are distributed mainly
to the powerful muscles which work the penis. In the female,
however, three pairs of moderately stout nerves are given off,
which go to the genitalia, but I have not been able to trace their
exact distribution.

Comparing the two figures, it is seen that the male and female
nervous systems are approximately of the same absolute length.
Since, however, the female flea is considerably larger than the
male, the nervous system of the female is relatively much
the shorter, and does not extend so far into the abdomen as that
of the male. Consequently the nervous system of the male is
the easier to dissect out.

As regards minuter details, the nerve-ganglia are seen to
contain a number of nuclei, representing the ganglion-cells,
which have a bilaterally symmetrical arrangement, showing that
each ganglion-mass is a fusion of a pair of ganglia. The nerves
which come off from the ganglia right and left contain small,
elongated nuclei, which are the nuclei of the connective tissue-
sheaths of the nerves. The connectives running between the
successive abdominal ganglia contain no nuclei, but the stout
connectives passing forwards from the metathoracic ganglion-
mass contain elongated nuclei similar to those of the peripheral
nerves.

450 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF

II. The Salivary Glands.

Having occasion to dissect some flea-larvae, I was struck by
the fact that the salivary glands of the larva differ greatly, both
in size and in complication of parts, from those of the adult flea.
I will begin with the adult, in which the glands are both smaller
and simpler in structure.

In the adult flea the salivary glands lie in the abdomen, right
and left of the stomach, in the form of two tiny pouches on each
side (PI. 27, B and C). Each pouch consists of large glandular
cells, which tend to stain very opaquely and have large nuclei.
The two pouches of each side give off each a short duct, and these
two ducts unite into a long duct running forwards on the side of
the body to the anterior thoracic region, where the two ducts from
the two sides of the body unite into a common salivary duct, which
runs forwards to open, doubtless, into the hypopharynx, as in
other insects. The paired salivary ducts have a very character-
istic appearance, being lined by a chitinous cuticle which shows
internally a system of rather irregular transverse thickenings.
This appearance is seen from the point where the ducts issue
from the glands up to a short distance from the spot where the
paired ducts unite to form the common salivary, duct ; the
structure of the ducts recalls to some extent that of a tracheal
tube, but the transverse thickenings are not so perfectly regular
as in the tracheae. At the point of union of the right and left
salivary ducts, however, there is a Y-piece in which the duct
diminishes in calibre to about half, and has no transverse
thickenings. External to the chitinous lining, the duct is
covered by a delicate layer of flat epithelium, which does not
show distinct cell-outlines, but has the appearance of a plas-
modial or syncytial layer of protoplasm with scattered nuclei.

The salivary gland of the adult flea, on account of its small
size, is not so easy to dissect out ; the glands of the female are
slightly larger than those of the male. On the other hand, the
salivary glands of the larva, which are plainly visible through
the body-wall of the living insect, are very easily dissected out.
All that is necessary is to decapitate the larva in such a way as
to cut off the first or first two thoracic segments, together with
the head, and then to press with the flat of a dissecting needle
gently along the body from behind forwards, so as to squeeze out

THE RAT-FLEA, CERATOPHYLLUS FASCIATUS BOSC. 451

the contents of the body-cavity through the cut end of the trunk.
The salivary glands sometimes come out as soon as the flea is
decapitated, without any such pressure, and it is easy to get
them on to a cover-slip and fix them.

Almost the only point in which the larval glands (PI. 27, A)
resemble those of the adult is in the characteristic structure of
the duct, which can be recognised immediately. Passing back
along the duct (d.), we come to a thin- walled dilated sac or
reservoir (r.), quite absent in the adult. Behind the duct a
tubule begins, composed of lightly staining glandular cells. After
a short course this tubule becomes continuous with the gland
proper, which is composed of darkly staining glandular cells, and
branches out into three lobes or diverticula, two of which run
forward (l.a. 1 , l.a. 2 ) and one backward (l.p.) alongside of the
digestive tract. All this arrangement of duct, reservoir, and
gland is, of course, duplicated on each side of the body, right
and left.

Accompanying the larval salivary gland are two elongated
pads or cushions of fat-body, which are very difficult to separate
from the gland without damaging the glandular lobes. In the
hinder of these pads of fat I found in many fleas a body which
looked exceedingly like a parasitic cyst, for which I mistook it at
first. Specimens mounted whole showed the " cyst " to be com-
posed of large cells in the interior, showing a. tendency in the
more advanced specimens to arrangement in longitudinal rows,
and enveloped by a layer of flat epithelium at the surface. At
its hinder end the " cyst " is prolonged into a delicate cord of cells
which could be traced in some specimens a long way back.
Further investigation showed, however, that when this " cyst "
was present on one side of the body it was also present on the
other side in exactly the same degree of development ; and further,
that when the "cysts" were absent in the fat-body on the level
of the salivary glands, they were to be found in other pads of fat-
body situated farther back, on the level of the intestine right
and left. Hence it was obvious that the supposed parasitic cysts
were simply the genital rudiments, situated farther forward in
the larvae of one sex than in the other. Whether it is the male,
or the female, in which they are situated farther forward, I
cannot say.

The striking differences between the larval and adult flea in

452 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF

respect to the salivary glands must be related to the difference in
their habits. The adult flea, I need not say, is a blood-sucker,
and in blood-sucking insects generally the function of the salivary
glands is believed to be that of producing a secretion which is
mixed with the ingested blood and prevents it from coagulating.
Incidentally the salivary glands of the adult flea, if crushed and
examined, can be seen to contain many yeast-like bodies of several
kinds, and it is supposed that it is these microbes which are
responsible for the local irritation and itching caused by the
puncture of the flea's proboscis. The flea-larva, on the other
hand, is more or less omnivorous, but appears to feed principally
on the faeces of the rat, as well as dirt and debris of all kinds.
Consequently its salivary glands have a function in the insect's
economy entirely different from that of the adult flea, assisting
probably in the digestion of the food, and their larger size in the
larva indicates a greater secretive activity than in the adult.

III. The Male Reproductive Organs.

The genitalia of the male flea exhibit a singular complication
of parts and of their arrangement, but are nevertheless very easy
to dissect out, and with a little care the entire reproductive system,
from testes to penis, can be mounted as one preparation, in which
every detail can be studied with the exception of those minuter
points of structure which require sections for exact study.

A general sketch of the various parts is given in Plate 28.
All the details of this sketch have been drawn from mounted
dissections with the camera lucida at a magnification of 150
diameters, reduced in the reproduction by one-half. At the same
time the relation of the various parts and their relative position
in the body has been checked by sketches of the whole system,
both of such parts of it as can be seen through the body-wall of
the flea without dissection, and also as it is seen when the abdomen
of the flea is freshly opened with the least possible disturbance of
the organs.

Most anteriorly are situated the two conspicuous testes (T , T.)
with their ducts coming off from them, and shaped somewhat like
a pear would be if the stalk (the duct) came off from its thicker
end. The testes lie dorsal to the stomach, but vary to some
extent both in size and arrangement. When the testes are of
large size, as in the younger males, they lie one in front of the

THE RAT-FLEA, CERATOPHYLLUS FASCIATUS BOSC. 453

other, and then the duct of the testis lying more anteriorly runs
straight back, while that of the testis situated more posteriorly is
coiled. When the testes are smaller, as in the older, more
exhausted males, they lie side by side and their ducts run straight
back.

When the testis is examined it is seen at once to consist of two
parts, a dilated bladder-like portion of ovoid shape, at the base of
which is a coiled tubular portion. The bladder-like portion
appears to be the testis proper (T ), while the coiled tubular
portion (ep. 1 ) recalls the structure in the human testis known as
the epididymis, and may be known conveniently by this designa-
tion. In one of my dissections I succeeded in uncoiling the
epididymis forcibly, by pulling on the duct (ep. 2 ). It was then
seen that the epididymis is a thin-walled tube, tilled with ripe
spermatozoa ; consequently, from the point of view of function,
the epididymis represents a vesicula seminalis, that is to say a
receptacle for the storage of ripe sperm.*

The calibre of the tubular epididymis narrows rapidly as it
passes on into the duct, which may be called here, as in other
animals, the vas deferens. The right and left vasa deferentia (v.d. 1 ,
v.d. 2 ) run back a little way and join to form the common vas
deferens (v.d. 3 ), but it can be seen very easily that the union of
the paired vasa deferentia is merely external and not internal,
since the lumina, or internal cavities, of the two ducts remain
quite distinct.

The common vas deferens runs to a set of glandular structures
which I regard as corresponding to a prostate gland, and consist-
ing altogether of four blind tubular diverticula ; a median pair of
short tubules, which maybe termed the median prostates (r.m.p.),
and a much longer pair of lateral tubules,